### PARTIAL OUTPUT (time limit hit; the model was still generating) ### === thinking so far === The user wants a complete Tetris-like falling-blocks puzzle game in a single self-contained HTML file. Let me plan this carefully to hit every requirement while making it visually polished and memorable. **Core requirements checklist:** 1. 10 wide × 20 tall playfield on canvas 2. Seven distinct tetromino shapes (4 squares each), each with its own color 3. Controls: ←/→ move, ↑ rotate, ↓ soft-drop, Space hard-drop 4. Rotation with wall/stack collision checks (no clipping) — I'll implement proper kick attempts (offsets: 0, ±1, ±2 columns, maybe up-shift for I piece) 5. Line clears with rows falling down, multi-line bonus scoring 6. Score, lines, level display; speed increases with level 7. Next-piece preview box 8. Game over when stack reaches top, visible game-over state, restart key 9. Clean, readable dark visual style **My approach to the design:** Visual style: dark, precise, "arcade terminal" aesthetic. I'll avoid the cliché neon-gradient look. Instead I'll go for a deep charcoal background with a subtly-gridded playfield, crisp flat-colored blocks with a slight inner shading (not gradients as decoration — just functional bevel shading on blocks to read as physical tiles, which is standard craft for block games and helps readability, not ornament). Actually, I should be careful with gradients here. I'll render blocks as flat fills with a 1px darker border and a subtle highlight edge — that's shading for depth, which is legitimate craft, not decorative gradient banners. Color palette: I'll pick 7 hues that are distinct but harmonious on dark backgrounds. I'll avoid the default Tetris "garish" palette and go for a slightly desaturated, richer set: - I: teal/cyan - O: amber/gold - T: magenta/purple... hmm, purple is fine as one piece color; it's not a "purple gradient landing page". Tetris traditionally assigns colors per piece and players expect distinct colors. I'll use: - I: #4FD6C9 (teal) - O: #F5C440 (amber) - T: #B587F2 (violet) - S: #7ED26C (green) - Z: #E86A6A (red) - J: #6C9BF2 (blue) - L: #F2913D (orange) These are readable and distinct. Layout: I'll build a side-panel layout — playfield centered/left, right panel with SCORE / LINES / LEVEL stats in a large monospace-ish display, NEXT preview box, and a controls legend at the bottom. I'll use a distinctive font — I can't load external fonts via CDN... wait, the user said "no external libraries, no internet resources, no images". So no Google Fonts either. Hmm — everything inline. So I must use system font stack. The instruction about avoiding Inter/Roboto/system-ui as "primary identity font" conflicts with "no internet resources". Given the explicit user constraint (no external resources), I'll craft identity through a carefully chosen monospace stack (`ui-monospace`, "SF Mono", "Cascadia Mono", "Consolas", monospace) which gives a terminal/arcade feel and is a deliberate choice, not a lazy default. Monospace throughout actually fits the retro-arcade identity strongly — that's my typographic voice here. For the big score number I can also render it with letter-spacing to feel like a segmented LED display. Fonts fallback: `font-family: "SF Mono", "Cascadia Code", "Consolas", "Menlo", ui-monospace, monospace` — deliberate monospace identity. Structure: - Container: dark charcoal (#0d1117-ish? Let me pick my own: #101216 page, panel #15171c, lines #232733). - Title: small caps label "BLOCKFALL" — I'll name the game something memorable: "TETRAMIN" or "BLOCKFALL". Let's call it "TETRAMINO"? Avoid trademark-adjacent "Tetris". "BLOCKFALL" is nice. Canvas rendering: - Canvas sized: cell size 30px → 300×600 canvas, but I'll render with devicePixelRatio scaling for crispness. Also draw grid lines faintly, block shading, and a "ghost" piece (subtle outline showing where the piece will land) — that's a craft addition that improves gameplay and looks great in dark style. Ghost rendering: outlined squares with low alpha, drawn as stroked rects. - The stack: each locked cell keeps its color; I store the board as 2D array of color indices. Rotation system: I'll define each tetromino as a matrix of 4 shapes with rotation states. Simplest robust approach: store shapes as arrays of rotation states (precomputed), or store as cells and rotate a square matrix. For I piece, 4×4 matrix rotation works; for others, 3×3 (T, S, Z) or 2×2 (O, and J/L as 3×3 with cells offset). Standard approach: represent each piece as list of rotation states defined explicitly (e.g., SRS-lite with 4 rotations each). I'll define shapes as coordinates and compute rotation by matrix rotation (rotate CW: (x,y) -> (y, maxX-1-x) or in matrix form). Easier: define each piece as a matrix (2D array), rotate by transposing+reversing rows. Piece definitions: - I: 4×4: [[0,0,0,0],[1,1,1,1],[0,0,0,0],[0,0,0,0]] — rotations of this in a 4×4 box give the classic vertical/horizontal states. Kick offsets: try dx in [-2..2], dy 0/1 (or dy = -1 then -2 for I when rotating near floor? Actually rotating vertical→horizontal near floor: shifting up helps. I'll try dy 0, -1, -2 in my kick sequence plus dx range). - O: 2×2 all 1s — rotation no-op. - T: 3×3 with [[0,1,0],[1,1,1],[0,0,0]] etc. Matrix rotation handles it. - J: 3×3 [[1,0,0],[1,1,1],[0,0,0]] - L: 3×3 [[0,0,1],[1,1,1],[0,0,0]]... wait L: [[0,0,0],[1,1,1],[0,0,1]] hmm. Let me use standard: J = [[1,0,0],[1,1,1],[0,0,0]]? That has top-left cell. Standard SRS: J spawn: [ [0,0,0],[1,1,1],[0,1,0]... no that's T-ish. Let me just define sensible matrices: T: [[0,1,0],[1,1,1],[0,0,0]] J: [[1,0,0],[1,1,1],[0,0,0]] L: [[0,0,1],[1,1,1],[0,0,0]] S: [[0,1,1],[1,1,0],[0,0,0]] Z: [[1,1,0],[0,1,1],[0,0,0]] O: [[1,1],[1,1]] — but 2×2 rotation (transpose/reverse) keeps it same; good. Though O in 2×2 sits fine. I: 4×4 as above. Rotation function for CW on NxN matrix: for each cell, new[x][y]... standard: rotated[y][x] = mat[N-1-x][y]? Let me define: rotate CW: result[r][c] = mat[N-1-c][r]. Check: element at (r,c) comes from original row N-1-c, col r. Yes that's CW rotation. CCW: result[r][c] = mat[c][N-1-r]. I'll support both? Up arrow rotates CW (and maybe shift+up CCW? Not required). I'll make Up = CW; also allow 'Z' key or... keep it simple: Up rotates CW. Maybe I'll add X for CW and Z/Shift for CCW as extra nicety — but requirement says up rotates. I'll keep Up = CW only to keep controls legend honest, plus maybe include CCW via holding... no, keep clean. Actually adding CCW on 'X' is a small nicety; but controls legend should list it. Requirement: "up arrow rotates" — satisfied. I'll add nothing extra to avoid clutter. Hmm, I'll add CCW on "X" and list it in legend — it's genuinely useful. Fine. Wall kicks: after rotating, test collision; if collides, try offsets: for each candidate (dx, dy) in kick list: dx from -2..2 (order: 0, ±1, ±2 — for I ±2 allowed), dy 0, -1, -2 (for floor lifts). I'll implement: attempt list = [[0,0],[-1,0],[1,0],[-2,0],[2,0],[0,-1],[-1,-1],[1,-1],[0,-2]]. Order matters for gameplay feel; fine. If all fail, don't rotate (keep original orientation). Movement: on ArrowLeft/Right, attempt move; if blocked, no move. I'll use DAS-ish behavior? Simple: keydown moves once, with key repeat handled by browser? Browser key-repeat fires repeated keydown — that works for left/right and down (soft drop). I'll implement my own repeat timing for horizontal (interval ~ 40ms? but simpler: rely on native repeat which is okay-ish but delay varies). I'll implement custom repeat: track held keys, initial delay 170ms, repeat 50ms — better feel. For soft drop: held down → speed up gravity (soft drop interval ~ 45ms), plus scoring? Standard Tetris gives +1 per soft-dropped cell. I'll add: each soft-drop-caused step +1 score... Requirement doesn't demand it; I'll add small soft-drop score (+1 per cell) since it's expected. Hard drop: +2 per cell dropped, then lock immediately. Gravity: base speed per level. I'll use classic-ish formula: dropInterval = max(60, 1000 * pow(0.85, level-1))? Or the NES-ish curve. Let me do: level starts 1, every 10 lines levels up. dropInterval = Math.max(50, 1000 - (level-1)*95)? That gets fast: level 10 → 145ms... hmm, level 11 → 50ms. Better: dropInterval = Math.max(40, Math.round(1000 * Math.pow(0.72, level - 1))). Level 1: 1000ms, L2: 720, L3: 518, L5: 262, L8: 96... L12: 40 floor. Reasonable. Or use guideline-ish: (0.8 - (level-1)*0.007)^(level-1)... complicated. I'll use the pow curve with a floor. Locking: when piece can't move down further, it locks after a short "lock delay" (500ms) if not moving — nice modern feel. But keep it simpler? Lock delay improves feel and lets rotation fix things; I'll implement a simple lock delay: when piece grounded, start timer 500ms; if moved/rotated or dropped off, reset (with cap of resets to avoid infinite). Keep it modest: lock delay 500ms, reset on successful move/rotate, capped at like 10 resets? Simple version: just reset timer on move/rotate while grounded; fine. Hard drop: immediately place. Line clear: detect full rows, mark them, animate? I'll add a brief flash animation (~250ms) where cleared cells blink/expand before collapsing — this is a nice signature visual moment. During animation, gameplay pauses. Implementation: on lock, compute full rows; if any, enter "clearing" state for ~280ms: draw those rows with white flash / shrink; then remove rows, update score/lines/level, spawn next piece. Scoring: guideline-like: {1:100, 2:300, 3:500, 4:800} × level. Plus soft drop +1/cell, hard drop +2/cell. Display multiplier feedback ("DOUBLE +300" etc.) as a floating toast in the panel or above canvas — I'll add a brief inline message in the side panel ("+800 ×LEVEL 3" style) and maybe draw in-canvas "TETRIS!" flash for 4 lines. I'll show a small "cleared" callout in the panel that fades. Keep it tasteful: a "last clear" line in stats: e.g. "TETRIS +2400". Game over: if a newly spawned piece intersects existing stack (or stack reaches top: if any row above spawn area is filled to overlap spawn — I'll trigger game over when spawn position collides). Visible game-over: dim overlay over playfield with "GAME OVER" text, final stats, and "press R to restart" — also draw on canvas itself (I'll draw overlay on canvas so it's clearly in the playfield). Restart key: R (also Enter?). Requirement: restart key — R. I'll support R and also a click on button? A restart button in panel too. And R works anytime? I'll allow R to restart from game over only (or anytime? mid-game restart could be accidental — I'll allow R anytime as "restart", that's common; but to be safe, allow R only on game over, and a small "R · RESTART" hint. Actually allowing R anytime is fine and handy; I'll allow it always but the hint shows on game over). I'll allow always — simpler mental model. Hmm risk: user pressing R mid-game loses progress; that's fine, it's stated as restart. Pause: P key for pause — nice extra; I'll add it with overlay "PAUSED". Not required but useful. Keep it. Game states: 'menu'? Requirement doesn't ask for start menu; I'll start the game immediately? Or a "PRESS ANY KEY / ENTER TO START"? A start state adds polish: show overlay "PRESS ENTER TO START" with the piece... Actually starting immediately on load may feel abrupt and first input gets swallowed. I'll add a ready state: overlay "ENTER ▶ START" drawn on canvas, game begins on Enter/any arrow? Just Enter (and maybe click). Keep it: Enter to start, R to restart, P pause. Controls legend lists these. Next preview: small canvas (or same canvas drawn? Separate small canvas in panel) showing next piece centered in a 4×4-ish box, drawn with mini cells. Also show... requirement only asks next. I could add a tiny "NEXT" label. I'll use a separate `` for preview (simplest, crisp). Stats panel: SCORE (big), LINES, LEVEL, plus BEST? localStorage best score — nice touch; allowed (local). I'll add "BEST" from localStorage. And "NEXT" preview above. And clear-callout line. Panel layout: I'll design a left playfield + right column: ``` [ Title: BLOCKFALL / subtitle ] [ NEXT preview box ] [ SCORE big number ] [ BEST ] [ LINES | LEVEL ] (two-up) [ LAST CLEAR: TETRIS +2400 ] [ controls legend list ] ``` Also a small live "speed" indicator? The LEVEL display conveys it. Maybe a subtle progress bar of lines until next level — nice: a thin bar under LINES showing (lines % 10)/10. That's a functional micro-visual, good. Signature moment: I want the line-clear animation to feel special — when clearing, the full row flashes white and cells "implode" toward the center with a brief vertical beam. I'll implement: during clearing state (280ms), for each cleared row draw cells with white fill shrinking scale based on progress, and a white sweep line. Also subtle screen response: tiny shake? A 2px canvas translate shake for 4-line clears — adds juice. I'll add slight shake on any clear (bigger for 4). Implement via canvas transform offset during clear anim. Tasteful. Also spawn: pieces appear with a brief fade-in? Maybe skip; keep clean. Dotted grid: draw playfield background as near-black (#0b0d12) with faint grid lines (#181b22). Border: 2px stroke (#2a2f3a) around canvas. Canvas inside a framed container with slight outer border and inner padding to create the classic arcade cabinet feel. Maybe add faint column shading every other cell? No, keep grid subtle. Block rendering craft: each block = flat color fill, then a slightly lighter top-left inner edge (1.5px) and darker bottom-right inner edge, plus 1px dark outline around each cell. This gives tactile tiles without gradients-as-decoration. I'll implement drawCell(x, y, colorIdx, {scale}) with: - fillRect base color - lighter shade line on top & left (rgba white 0.28 alpha, thin) - darker on bottom/right (rgba black 0.35) - outer stroke rgba(0,0,0,0.4) 1px Alternatively draw with rounded 2px corner radius for a modern tile feel? Rounded rects at 30px cell with 3px radius look slick. I'll use rounded corners + inner bevel lines. Also small inner gap (cells drawn with 1px gap so grid shows subtly) — actually a 1px inset makes tiles read crisply. I'll draw cells inset by 1px with radius 3. Ghost piece: outline only, stroke color of piece at alpha 0.35, dashed? Solid thin stroke with low alpha, plus faint fill alpha 0.06. Good. Canvas resolution: logical 10×20 cells at 30px = 300×600; style width 300px (or set via CSS aspect ratio). I'll compute DPR-scaled canvas: canvas.width = 300*DPR etc., ctx.scale. CSS width fixed ~ 340px? Keep cell 30 → width 300 CSS px. On smaller screens, scale via CSS max-width and aspect-ratio. I'll set canvas style width:300px; height:600px; and container uses media queries to shrink (CSS transform scale? simpler: use `--cell` sizing? For canvas, easiest is fixed logical size and CSS `width: min(300px, ...)`. Since drawing is DPR-based, CSS scaling of canvas works fine (browser scales bitmap). I'll set canvas style width via CSS (width: 300px; height: 600px) and add media query to shrink to 260/220 for small screens. Keep simple: canvas CSS width 300px, and on narrow viewport use width: min(320px - paddings...). I'll do `.stage canvas { width: 300px; height: 600px }` with a media query fallback `width: min(300px, 76vw)` and proportional height via aspect-ratio. Hmm canvas needs explicit aspect: set `aspect-ratio: 1/2`? width min(300px, 74vw); height auto via aspect-ratio 1/2. Since intrinsic bitmap is 300x600, height auto with attribute-based ratio would work: I can just set CSS width and height computed via aspect ratio using `height: calc(...)`? Simpler: wrap in element with aspect-ratio; or set both width and height in CSS with a CSS variable scale. I'll do: canvas { width: var(--w, 300px); height: calc(var(--w,300px)*2); } and set --w responsively. Eh, overkill — I'll set `width:100%` inside a fixed-width column and rely on aspect-ratio: `canvas { width:100%; aspect-ratio: 1/2; height:auto }` — modern browsers support aspect-ratio on replaced elements with height:auto? aspect-ratio works with both axes auto-derived. Setting width:100%; height:auto; aspect-ratio should give height = width*2 for the content box. For canvas (replaced element), aspect-ratio applies. Yes, works in modern browsers. Do that for both canvases (preview: aspect-ratio 1/1 with width 84px? preview logical 96×96? I'll make preview canvas logical 4 cells × 24px = 96... plus padding. Let me make preview canvas 100×100 logical? Piece max 4 wide (I). Use cell 22, canvas 96×88? Simplest: 104×104 logical, draw piece centered with cell 24. CSS width 104px? Set canvas width 104px via CSS fixed; fine.) Keyboard handling details: - Prevent default for arrows/space (space scrolls page). - keydown: handle via switch on e.code (ArrowLeft, ArrowRight, ArrowUp, ArrowDown, Space, KeyX, KeyR, KeyP, Enter). - Left/right/down handled with custom repeat: on keydown (if !e.repeat) trigger action and record heldTime; on keyup clear. Loop uses timestamps. Actually for left/right I'll implement: heldKeys map; in game loop, if left/right held: if elapsed > delay and lastRepeat+interval, move. Simpler robust: on keydown, move once, record direction & start; in loop, while held, after 170ms delay, move every 50ms (DAS). Down: while held, soft-drop every 45ms and add +1 score per step; also keydown triggers immediate soft step. Space: hard drop on keydown (no repeat — e.repeat guard). Up: rotate CW on keydown (guard repeat? allow repeat? Up repeat rotate could be accidental spam; I'll ignore e.repeat for Up/X so one per press). Actually letting Up repeat rotate is chaotic; block e.repeat for rotation. - Also when game paused/menu/gameover, ignore movement. Rotation implementation with kick attempts as described. After successful rotation, if grounded, reset lock timer. Collision: function collides(mat, x, y): for each filled cell, bx = x + cx, by = y + cy; check bounds bx in [0,W), by < H, and by >= 0? If by < 0 (above top) — during spawn pieces might have cells above 0; I'll allow y<0 as free (no collision, but clamp: if by < 0, skip; but also can't move up beyond). For rotation kicks with dy=-1 when at top, cells above 0 are fine (no blocks there). Also forbid bx out of range and by >= H. Also on move left/right, cells above top (y<0) fine. Spawn: piece x = Math.floor((W - pieceWidth)/2) computed from matrix bounding box; y = -top offset? Spawn at y such that piece appears just below top: I'll spawn y = 0 but if matrix has empty top rows... For 3×3 T etc. spawn row 0 shows top row. Standard: spawn with piece's lowest? Keep simple: y = 0 (matrix row 0). For I 4×4 with fill at row 1, spawn y=-1 so filled row is at y=0? I'll compute spawnY = -matrixTopEmptyRows? Better: spawn y = 0 - topOffset where topOffset = number of empty leading rows? Actually easier: y = 0, and if collides at spawn → game over. But pieces with empty first row would show nothing at top briefly. Compute minY of filled cells in spawn matrix; set y = -minY so topmost filled cell is at row 0. Then if collides → game over. Good. Game over condition also: when stack reaches top — covered by spawn collision (if stack is tall, new piece can't fit). Additionally "stack reaches the top" strictly: piece spawn blocked = game over. Good. Also when locking a piece with any cell above row 0? If piece locks partially above top (y<0 cells)... with spawn topmost at 0, pieces never go above 0 except during kick dy=-1; if lock leaves cell at y<0... collision check allows y<0 cells to exist; when locking, if cell y<0, that's game over (out of field). I'll check: after lock, if any cell of piece is at y < 0 → game over. Fine. Bag randomizer: 7-bag for fairness — nice touch, easy. I'll implement shuffled bag. Line clear flow: ``` lock(): merge cells into board; check gameover; find full rows; if rows: state='clearing', clearStart=now, store rows list, shake amp; sfx? no audio? Audio via WebAudio API beeps — no external resources, WebAudio is local. Should I add sound? It's nice but adds complexity; user didn't ask. I could add subtle WebAudio clicks (rotate, drop, clear chord) with a mute toggle. It elevates the experience ("alive"). I'll add minimal synth sounds: move tick (short blip), rotate, lock thud, clear rising arpeggio, harddrop thud, gameover descend. Mute toggle button in panel (M key + clickable). Keep audio code compact (~40 lines). Yes — adds craft. I'll implement tiny AudioCtx with osc + gain envelopes, no files. ``` During clearing: game loop draws board normally but for cleared rows draw animated: white bars shrinking; skip spawn of next until anim ends. Then remove rows (splice top-down), update lines/score/level, recompute speed, show callout, spawn next. Score display formatting: score formatted with grouping? Just raw number with monospace, maybe padded. I'll pad lines/level. Score displayed as plain number (can be large). Use font-variant-numeric: tabular-nums. Panel style: dark cards? I want clean, readable: right column with section labels (small letter-spaced uppercase labels, color #6b7280-ish muted) and values in bright #e6e9f0. Boxes: subtle bordered rows (1px #222630 background #111418). Legend: two-column key/action with kbd-styled keys (bordered chips). kbd chips: background #1a1d24, border #2c3140, radius 4, padding 2px 7px. Title: "BLOCKFALL" with letter-spacing, maybe a small block glyph made of CSS? I'll add a tiny inline SVG? No images allowed but inline SVG is fine (not an image resource, it's markup). I could make a small 4-square glyph next to title using CSS boxes — simple divs. Keep minimal: title text + small 3-dot accent using CSS. Or skip decoration entirely and let typography carry it. I'll add a small tetromino-ish mark: two offset squares in piece colors next to title — subtle, purposeful (it identifies the genre). Fine. Overall page: centered layout, dark bg #0e1013 with very subtle radial vignette? Careful: no large gradient ornaments. I'll use flat bg #0f1114 plus faint dot-grid? Keep flat and clean; a barely-visible vertical column separation via border lines. Header row: title left, game wordmark. Footer hint: small muted line "ENTER to start · R restart · P pause". Frame around playfield: I'll give the canvas a border (2px #2a2f3a) and an outer glow? No glow. Just border + panel separation line. Also draw on canvas: 1px inner border and maybe the top "danger zone" shading? When stack nears top, rows 0-2 could tint red slightly as warning? Nice functional touch: tint top 2 rows with subtle red hatch when stack height ≥ H-4? I'll add subtle warning: if any filled cell in rows 0..3, draw a faint red tint line at top. Keep it minimal: draw a thin red strip (alpha 0.12) over the highest-danger zone. Actually simpler: skip; game over overlay is enough. Hmm, I'll add a subtle top-row danger tint — small, functional. Maybe skip to avoid clutter. I'll include a faint danger line above row 0? Skip. Focus on solid core. Pause overlay: canvas dims + "PAUSED / press P". Game over: canvas dims (alpha 0.82 black), big "GAME OVER" text, score summary lines, "PRESS R TO RESTART" blinking? Static with blinking hint (draw text with alpha pulsing based on time — subtle). Ready state: "BLOCKFALL" small + "PRESS ENTER" — or since title's in panel, overlay says "READY" + "PRESS ENTER TO START". Good. Now code structure: HTML skeleton: ```html BLOCKFALL
...title + accent...
``` Wait: canvas id="board" element with width/height attributes set in JS (DPR aware). I'll create attributes: set canvas.width = W*CELL*DPR, canvas.height=H*CELL*DPR, style width 100%. Actually simpler: define logical size in JS: ```js const W = 10, H = 20, CELL = 30; const dpr = Math.max(1, window.devicePixelRatio||1); cv.width = W*CELL*dpr; cv.height=H*CELL*dpr; ctx.setTransform(dpr,0,0,dpr,0,0) // then draw in logical coords ``` And CSS: canvas { width:100%; aspect-ratio: 1/2 } within stage having width: 300px (or clamp). I'll set .stage width: clamp(240px, 30vw, 300px)? To keep panel & stage fitting on ~desktop: stage 300px + panel 240px + gaps = ~570px; fine on desktop. Mobile: media query stacks them; stage width min(300px, 88vw). I'll write CSS accordingly. Preview canvas: width 104, height 104 (logical), DPR-scaled similarly; CSS width 104px → I'll also do width:100% inside fixed box? Fixed 104 fine. Now JS core: ```js const SHAPES = { I: { color: '#3fd1c4', matrix: ... }, ... }; ``` Colors as key per piece; store board cells as color index + also need piece color for drawing; board stores color strings directly (board[r][c] = color string or 0). Simpler: store color string. Pieces as matrices of 0/1 (numbers). Represent piece object: { key, matrix, x, y }. rotate(matrix): ```js function rotateCW(m){ const n=m.length; const r=[]; for(let i=0;i=W||by>=H → true; if by>=0 && board[by][bx] → true. by<0 allowed (above field). Also for horizontal move at spawn, by<0 cells skip collision, fine. grounded: collide at y+1. Locking piece into board: ```js function merge(p){ let above=false; for cells: by>=0 ? board[by][bx]=p.color : above=true; if(above) gameOver(); } ``` Wait cell at by<0 → stack reached top → game over. Also spawn collision → game over. clear check rows. Timing loop: ```js let last=0; function frame(t){ requestAnimationFrame(frame); ... } ``` Use performance.now-based dt. Accumulate gravity counter. State machine: state ∈ {'ready','play','clear','over','pause'}. When 'clear', animate then resume. Pause freezes timers (store pause start; on resume adjust timers? Simpler: pause by not accumulating: use drop counter as accumulated ms and only add dt when playing). Since I use counters, pausing naturally freezes. Lock timer: lockT accumulated only in play. Good: structure loop: ```js function loop(now){ requestAnimationFrame(loop); const dt = Math.min(60, now-lastT); lastT=now; if(state==='play'){ update(dt); } if(state==='clear'){ clearT += dt; if(clearT>=CLEAR_MS) finishClear(); } render(now); } ``` update(dt): handle DAS repeats (using heldLeft/heldRight timestamps with dt accumulation), gravity: dropAcc += dt; if grounded: lockAcc += dt; if lockAcc>=LOCK_MS lock(); else gravity falls: while dropAcc >= interval: try move down; dropAcc -= interval. If soft drop held: use softInterval and add +1 per row moved (only for gravity-caused? Typically soft-drop score counts each row dropped while pressing down; I'll implement: when soft held, gravity uses softInterval (45ms) and each successful down-step during that adds +1). Also pure gravity steps no score (or +1 per cell? Guideline gives nothing for pure gravity). Keep +1 only when down held. DAS: variables: dasDir ( -1/0/1 ), dasT (held ms), lastMoveRepeat. On keydown Left: move(); dasDir=-1; dasT=0. On keyup: if dasDir matches, dasDir=0 (and if other key still held, switch? Track per-key: heldL, heldR booleans; dasDir = heldL? -1 : heldR? 1 : 0; re-trigger? Edge cases fine). In update: if dasDir: dasT += dt; if dasT > DAS(170): repAcc += dt? Use: while dasT > DAS + k*ARR... simpler: arrAcc += dt; if dasT>DAS && arrAcc>=ARR(45): move(dasDir); arrAcc=0. But arrAcc accumulates from start; set arrAcc=-ARR initially? Initialize arrAcc=ARR so first repeat at dasT>DAS. Good enough. Soft: softHeld bool; in gravity section: interval = softHeld ? 45 : curInterval; and when stepping down due to gravity while softHeld → score+1 (only if actually moved due to gravity step, not the keydown immediate move? keydown down triggers immediate gravity step too: I'll call stepDown(true) adding +1). Note: both DAS-style and gravity — down uses gravity accumulator (no separate repeat) — pressing down just speeds gravity; also gives immediate step: on keydown, force dropAcc += big? I'll on keydown call stepNow(): if can move down, move, +1 score, dropAcc=0. Hard drop: while can move down: move; distance count; score += dist*2; lock immediately (skip lock delay); play sound. Lock: merge; check spawn? After lock, spawn next from bag: bag refill; nextPiece set; if collides at spawn → gameOver. Also immediately after lock compute clears. Game over: state='over'; update best (localStorage); draw overlay in render; play sound. Render function: - clear canvas: bg fill (#0b0d10), grid lines each cell (#141922 alpha?). I'll draw grid: strokeStyle rgba(255,255,255,0.045), 1px lines every CELL. Plus outer border rect stroke (#262b36) 2px inset? The CSS border covers outer; I'll draw 1px inner line anyway? Skip, CSS handles. - shake: if clearing, translate small random offset scaled by amplitude decay. - draw settled cells: board[r][c] color via drawCell. - clearing rows overlay: progress p=clearT/CLEAR_MS; draw white rects over those rows: alpha 0.9*(1-p) shrinking height toward center? I'll draw full-row white bar with alpha ease, and each cell scaled down: draw white rounded rect of width CELL*(1-p) centered. Also sweep beam: horizontal line at row center with alpha. Keep code modest: white row bar: height CELL*(1-p*?) Let me: for each row: draw white bar height CELL with alpha (1-p)*0.85; then black gaps? Simplest visually good: white bar fades while shrinking vertically into a thin line: draw rect (x=0,w=W*CELL, y = rowY + CELL*p/2, h = CELL*(1-p)). That collapses into a white line then vanishes. Plus shake. Nice. - current piece cells (skip if clearing state? During clear, piece is already merged; next piece not spawned until finishClear → draw nothing active during clearing; fine). - ghost: if state play and piece: compute drop y = maxOffset where no collision; draw outline cells at that y (skip cells of piece? ghost all filled cells at target pos). alpha stroke color 0.3, fill 0.05. - overlays per state (ready/pause/over) drawn last: dim rect rgba(5,6,8,0.78) full; centered text: monospace, letterSpacing? Canvas letterSpacing via ctx.letterSpacing (Chromium supports; Safari/Firefox may not — set with fallback: set ctx.font and manually space? I'll just use ctx.font = '600 26px ...' and rely on natural spacing; or manual char spacing by drawing chars individually — easy small helper for headline text with tracking. I'll write drawTextCentered with manual tracking for the overlay titles.) Game over overlay content: "GAME OVER" big, "SCORE 12 340" (formatted), "LINES 23 · LEVEL 2", "PRESS R TO RESTART" small pulsing (alpha 0.5+0.4*sin). Ready: "BLOCKFALL" small? maybe "READY" + "PRESS ENTER". Pause: "PAUSED" + "P to resume". Danger check for "stack reaches top": also show warning? skip. Preview render: clear, draw next piece matrix centered: compute bounding box of filled cells; cell size 22 (I piece 4×4 → 88 fits in 104 with margins). Center via bbox. Draw with drawCell-like mini function scaled. Also animate? Static is fine; maybe subtle idle bob? Keep static crisp. Stats DOM updates: score el, best el, lines el, level el, progress bar width (lines%10)*10%, lastClear text. Update on changes via function syncUI(). Format score with toLocaleString? Use grouping with thin space: score.toLocaleString('en-US') gives commas — fine? Commas fine. Last clear callout: text like "TETRIS +2400" or "DOUBLE +600"; set CSS opacity animation via re-adding class or CSS transition; small function: el.textContent = msg; el.classList.remove('pop'); void offsetWidth; add 'pop' → CSS animation fade-slide. Good. Sounds (WebAudio): ```js let actx=null, muted=false; function beep(freq, dur, type, vol, slide){ ... } ``` Implement noise-free: functions: - sfxMove: tiny 4ms blip (freq 220? use square low vol) — maybe skip move sound (too noisy). I'll include very subtle move tick? Many games have it; at DAS repeat 45ms it'd buzz. Skip move sound. - sfxRotate: short 660Hz sine 30ms low vol. - sfxStep/soft: skip. - sfxLock: 110Hz square 60ms + click. - sfxHard: 90Hz + quick. - sfxClear(n): arpeggio: for i level → level up, sfx, maybe brief callout "LEVEL 3". Speed recompute: curInterval = intervalFor(level). intervalFor(level): ```js function dropInterval(lv){ return Math.max(45, Math.round(1000*Math.pow(0.72, lv-1))); } ``` Level 1 1000 → too slow start? 1000ms fine classic. Maybe start 850? pow(0.75,lv-1)*833? Keep 1000 baseline; L2 720... good. Bag: ```js const bagKeys = shuffle(['I','J','L','O','S','T','Z']); ... function nextFromBag(){ if(bag.length===0) bag=shuffle(KEYS.slice()); return bag.pop(); } ``` Maintain queue: current piece + next; on lock spawn: current = next; next = pullBag(); renderPreview. Piece factory: function makePiece(key): {key, color, matrix: SHAPES[key] cloned (deep copy) — need fresh matrix per piece for rotation mutation (we rotate matrix in place). Spawn: x centered by bbox, y = -topEmpty rows? compute minY. Let me compute spawn: ```js function spawn(key){ const m = cloneMatrix(SHAPES[key].m); let minY=99,maxXw; compute bbox: for filled cells minY=minY? minX, maxX. x = Math.floor((W-(maxX-minX+1))/2) - minX; y = -minY; piece={key,color,matrix:m,x,y}; if(collide(m,x,y)) gameOver(); } ``` Hmm careful: if piece spawns overlapping stack (collide true) → game over. Also for spawn y = -minY: topmost filled cell at row 0 — good. But wait: O piece matrix 2×2: minX=0,maxX=1, width 2 → x=4. Fine. Rotation mutation: piece.matrix = rotateCW(piece.matrix) attempt; plus kicks. If success: sfx, if grounded reset lockAcc; dropAcc reset? Rotation doesn't reset gravity; just lock delay. Keep gravity running. Movement left/right: tryX = x+dx; if !collide → x=tryX; if grounded reset lockAcc? Resetting lock delay on every DAS move at wall could allow infinite stall — cap lock resets: I'll not reset lock on horizontal wall-pressed moves when no actual movement (only reset when piece actually moved). And cap: count lock resets max 8? Add simple cap: if lockResets<15 reset else no. Fine — small guard. Gravity step in update: attempt y+1; if collide → grounded; grounded handling: if !grounded: y++ (success), if softHeld score++ and maybe reset? dropAcc -= interval. If grounded (cannot move): set grounded=true? Track piece.grounded bool; when grounded, lockAcc accumulates; if piece becomes ungrounded (via rotation lift etc.) lockAcc resets. Handle: each update: if collide(y+1) → grounded: lockAcc+=dt; if lockAcc>=LOCK(500): lock. else if piece.grounded was true and now not: lockAcc=0. Also gravity while grounded: dropAcc should be held (don't accumulate into steps). I'll reset dropAcc when grounded to avoid burst after unlock? When un-grounding (kicked up), reset dropAcc=0. OK. Also when soft drop held & grounded: pressing down with lock delay — space/… down while grounded: does nothing (can't move). Optionally pressing down while grounded could trigger faster lock? Some games do; I'll keep lock delay (prevents accidental instant locks). Fine. Hard drop: loop while !collide(y+1) y++, steps++; score+=steps*2; merge/lock. distance tracked. Line clear finish: ```js function finishClear(){ // remove rows const rowsKept=[]; for r: if(!fullRows.includes(r)) keep else skip; board = board.filter(row => !fullRows.includes(rowIdx)) ... build new board: const remaining=[]; for(r=0;r0: shake amp = 3+2n? store shakeT. Rendering pieces during 'clear': piece=null during clear (we set currentPiece=null on lock, spawn after). Good. Ghost only in play. Now, one subtlety: rotating near floor lifts piece (dy=-1) — could lift above spawn? cells above 0 allowed; but then piece might sit at y=-1 floating with cells above row 0; when it later can fall it does. Fine. Also merging with y<0 cells → game over. Edge: O piece rotate — matrix 2×2 rotates to itself (since all filled? [[1,1],[1,1]] rotated equals same). No-op fine. I piece 4×4 rotate: spawn [[0,0,0,0],[1,1,1,1],[0,0,0,0],[0,0,0,0]]. CW: r[i][j]=m[3-j][i]: row0: j=0..3 → m[3][0..3]=0,0,0,0 → empty; row1: m[2][0..3]=0s; row2: m[1][*]=1 1 1 1; row3: m[0][*]=0s → vertical column at col 2. Good (col 2 of 4 → occupies x+2). Kick tests handle walls. T spawn [[0,1,0],[1,1,1],[0,0,0]] → CW gives [[0,1,0? compute: r[0][0]=m[2][0]=0;r[0][1]=m[1][0]=1;r[0][2]=m[0][0]=0 → [0,1,0]; r[1][*]=m[2? r[1][j]=m[3-1-j? n=3: r[1][j]=m[2-j][1]: j0:m[2][1]=0;j1:m[1][1]=1;j2:m[0][1]=1 → [0,1,1]; r[2][j]=m[2-j][2]: m[2][2]=0, m[1][2]=1, m[0][2]=0 → [0,1,0]]. So CW of T-pointing-up gives T pointing... rows: [0,1,0],[0,1,1],[0,1,0] — pointing right? top cell at (0,1), arm at (1,2) — that's pointing right. Fine, standard-ish. Colors dictionary: ```js const PIECES = { I:{c:'#35cfc0', m:[[0,0,0,0],[1,1,1,1],[0,0,0,0],[0,0,0,0]]}, J:{c:'#5f8ef4', m:[[1,0,0],[1,1,1],[0,0,0]]}, L:{c:'#f0923a', m:[[0,0,1],[1,1,1],[0,0,0]]}, O:{c:'#e8b83a', m:[[1,1],[1,1]]}, S:{c:'#6ed168', m:[[0,1,1],[1,1,0],[0,0,0]]}, T:{c:'#a86ee8', m:[[0,1,0],[1,1,1],[0,0,0]]}, Z:{c:'#e06565', m:[[1,1,0],[0,1,1],[0,0,0]]}, }; ``` Hmm J blue #5f8ef4 vs I teal — distinct. T violet #a86ee8 vs J blue could be closeish at low sat? They're distinguishable (violet vs blue). Fine. drawCell implementation: ```js function cellPx(x,y,size){...} function drawCell(px,py,s,color){ // px,py top-left in logical px const g=1, r=Math.max(2, s*0.1); // corner radius 3 for 30 ctx.fillStyle=color; roundRect(px+g? Use inset: x=px+1.5? For crispness with DPR... Since ctx scaled by dpr, logical 1px lines are crisp-ish. I'll inset by 1: draw roundRect(px+1,py+1,s-2,s-2,3) fill base; then bevel: ctx.strokeStyle rgba(255,255,255,.22) line along top-left inside; simpler: draw two thin rects: highlight: fillStyle rgba(255,255,255,.16) rect(px+2? Let me design: - base fill rounded rect inset 1 - inner shadow bottom: rgba(0,0,0,0.28) rect(px+1, py+s-5?, s-2, 4) — strip along bottom (rounded? tiny strip, acceptable square bottom inside rounded? The bottom corners rounded r=3 would leave strip corners poking — inset strip by 3 horizontally? Just draw strip width s-8 centered? Simpler: use a slightly darker variant color for bottom strip computed via shade(color,-25%)? Precompute darker/lighter from hex. ``` Compute shade util: ```js function shade(hex, amt){ // amt -100..100 const n=parseInt(hex.slice(1),16); ... } ``` Precompute for each color: base, lite (lighten 30), dark (darken 30). Then drawCell: - fill roundRect base (inset 1, radius 3) - fill rect top strip (px+1+2?, height 3) color lite alpha .55 → gives bevel; plus left strip similar? Classic bevel: top+left lite, bottom+right dark. With rounded rect corners, use two rounded rects overlaid? Easiest crisp method: draw base rounded rect dark (the outline color = darker), then draw base rounded rect slightly smaller positioned up-left in main color, leaving dark showing on bottom-right = bevel illusion. I.e.: 1) fill roundRect(px+1,py+1,s-2,s-2,r) with dark color (shade -35) 2) fill roundRect(px+1,py+1,s-3? and shift: main rect (px+1, py+1, s-4, s-4)? That leaves dark L-shaped on right/bottom ~2px and lite? Then add lite: fill roundRect small strip at top-left lite. Simpler and reliable: 1) outlineRect dark fill full (px+1..s-2, r=3) 2) main color roundRect(px+1,py+1,s-4? hmm the dark shows at right and bottom edges of thickness ~ (s-2)-(s-4)=2? If dark rect is s-2 tall/wide and main rect is s-3? Let me param: dark rect: x=px+1,y=py+1,w=s-2,h=s-2. main rect: x=px+1,y=py+1,w=s-4,h=s-4 → dark visible band thickness 2 along bottom & right? width difference: dark right edge at px+1+s-2=px+s-1; main right edge px+1+s-4=px+s-3 → band 2px. Bottom similar. But main rect same origin → dark band only bottom-right; top-left shows dark? No: main covers top-left from same origin; top-left corner region: main starts at same point, so dark hidden except... dark rect's top-left corner area is covered by main (both start at px+1). So dark visible only where main ends earlier: bottom & right → 2px dark band bottom/right. Then add lite: draw thin lite strip top-left inside main: rect(px+2,py+2? I'll draw lite rect (px+2, py+2, w=s-6? h=3) top strip and left strip (px+2,py+2,3,h=s-6?) with alpha .45. Could double-draw overlapping corner fine. Result: base flat main, 2px dark bevel bottom/right, 3px lite top/left, rounded corners. Cohesive tile look. For ghost: stroke roundRect only. Rounded rect helper: ```js function rr(x,y,w,h,r){ ctx.beginPath(); ctx.moveTo(x+r,y); ... arcTo... ctx.closePath(); } ``` Use arcTo-based path then fill/stroke. Mini cell for preview: reuse drawCell with s=20? drawCell uses fixed sizes... make drawCell(px,py,s,color, lite, dark). radius scaled: r=s*0.1. Grid: draw vertical/horizontal lines: for i 1..: moveTo(i*CELL+0.5? With DPR scaling, 0.5 offsets in logical px produce crisp when dpr whole? At dpr=1 (some laptops), 0.5 offset needed; with dpr=2, lines at 0.5 logical = 1 device px → crisp too. Use ctx.strokeStyle='rgba(255,255,255,0.05)'; draw all lines as single path with 0.5 offset. Also maybe stronger every? Keep uniform subtle. Also I want slight vignette? no. Board bg fill '#0c0e12'; grid '#12151b'-ish via rgba white .05. Panel HTML/CSS: ```css :root{ --bg:#0e1013; --panel:#13161b; --line:#232833; --ink:#e4e7ee; --muted:#77828f; --accent:#35cfc0; (teal as accent, matches I piece; used sparingly) } body{background:var(--bg); color:var(--ink); font-family: mono stack; display:flex; min-height:100vh; align-items:center; justify-content:center;} .wrap{padding: 28px 20px; width: max-content? } ``` Layout: `.game{display:flex; gap:22px; align-items:stretch}`. Stage: `.stage{background:var(--panel); border:1px solid var(--line); padding:12px; border-radius:12px}` containing canvas (border? canvas itself has bg drawn). Canvas border-radius? Canvas content square; apply border-radius on canvas with overflow? Canvas renders its own bg; radius on canvas element would clip corners visually? border-radius on canvas does clip rendering? It does clip (border-radius clips replaced content? For canvas, border-radius does clip the painted content — yes, CSS applies to replaced elements). But blocks near corners would clip oddly; keep canvas square with border:1px solid var(--line). Panel: `.panel{width:232px; display:flex; flex-direction:column; gap:14px}` with sections styled: each `.card{background:var(--panel); border:1px solid var(--line); border-radius:10px; padding:12px 14px}`. Typography: labels `.label{font-size:10px; letter-spacing:.18em; color:var(--muted); text-transform:uppercase}` values big: score value `font-size:26px; font-weight:700; letter-spacing:.02em; font-variant-numeric: tabular-nums`. Masthead: row above both columns spanning: title "BLOCKFALL" + tiny mark + right side maybe tagline "a falling-blocks puzzle". Keep single masthead above the flex row: display:flex; justify-content:space-between; align-items:baseline. Title font-weight 800 letter-spacing .3em? "BLOCKFALL" with 0.24em tracking, plus mark. Tagline muted small: "TEN BY TWENTY · SEVEN PIECES · ONE STACK"? A bit precious... "10×20 · seven tetrominoes · soft & hard drop" hmm. Keep: tagline "falling-blocks puzzle · v1". Something restrained: "TEN COLUMNS · TWENTY ROWS" as a nice nod. I'll put on the right: "10 × 20 · 7 PIECES" muted mono. Good. Legend keys with kbd chips: grid two columns rows: ``` ◀ ▶ MOVE (keycap ← →? Use characters "←" arrows? Use text "←→". kbd chips: ← → | ↑ rotate | ↓ soft | space hard | enter start | R restart | P pause | M sound) ``` Rows: label + chips. Use grid: each item `display:flex; justify-content:space-between` with keys left chips, action right muted? Or action left label + chips right. I'll do: `.keyrow{display:flex;align-items:center;justify-content:space-between;}` left: action name (small caps muted), right: kbd chips. 8 rows stacked tight (font 12px). Compact card. kbd chip css: `.kbd{font:11px/1 inherit; border:1px solid #2b3040; background:#191d26; padding:3px 6px; border-radius:5px; color:#c6ccd6; box-shadow: 0 1px 0 #000 inset? subtle}`. Progress bar for next level: `.bar{height:4px;background:#1b1f28;border-radius:2px}` inner fill width var accent teal. Under LINES card. Level card: two-up grid lines & level side by side; plus BEST. Arrange stats card: SCORE big; row: LINES | LEVEL with mini bars? Structure: Card 1 (NEXT): preview canvas centered + label. Card 2 (SCORE): big number; small row: BEST value. Card 3 (PROGRESS): two cells LINES & LEVEL with values; below thin bar with caption "next level in N lines"? Show bar only. Bar fill = (lines%10)*10%. When level up resets to 0 naturally. Add tiny text right of bar: "LV {n} speed {ms}"? Could show current drop ms — nerdy nice: "SPEED 453ms". I'll include speed ms small muted. Hmm keep: LINES | LEVEL values; bar; tiny caption row: "NEXT LEVEL AT 10 LINES"? verbosity... I'll include speed display as tiny right-aligned muted in card header ("650 MS" updates). Nice functional detail. Card 4 (LAST CLEAR): value text e.g. "—", on clear "TETRIS +3200". Card 5 (CONTROLS legend). Footer card? Mute button + small footer text "R restarts anytime". Buttons: mute button styled chip. Place mute in masthead right or in controls card footer. I'll place in masthead: small button "SOUND: ON". Plus M key. Keep in legend card bottom row: a row "SOUND [M] [toggle chip button]"? Simpler: put a button in the controls card: `.toggle` full-width row? Let me structure controls card rows including SOUND with clickable chip acting as toggle (button element). Clickable chip toggles mute. Also mention R/P/Enter in legend. Danger: stack nearing top: I'll add subtle red tint on canvas rows 0..1 when stack height > H-6? Implement: compute topFilledRow; if <=4? draw red rgba(224,80,80,alpha .05+t) over top rows... Only when close: if any filled cell within rows 0..3 → draw pulsing danger strip across top 4 rows alpha .04+.03sin — subtle warning. I'll implement lightly: if dangerRows>0: fill rgba(224,70,70, 0.05+0.04*Math.sin(t/300)) rect over top 4 rows. Tasteful; adds "alive" feedback. But maybe it distracts... it's subtle enough. Include. Responsive: media query max-width 720px: .game{flex-direction:column; align-items:center} panel width 100% max 340px. Masthead adjusts. Fine. Also prevent arrow/space scrolling: e.preventDefault for handled codes. Also handle blur → pause? window blur auto-pause: nice. If state==='play' on blur → pause. Include. Key handling code: ```js const HOLD = { left:false, right:false, soft:false }; document.addEventListener('keydown', e=>{ ... }); ``` Ignore if e.metaKey etc? fine. Handle codes: - Enter: if state ready or over → start/restart. (Also R restarts anytime.) - KeyR: reset anytime. - KeyP: toggle pause if play/pause. - KeyM: toggle mute. - ArrowLeft/Right: if play: tryMove(dx); set hold & das reset. preventDefault. - ArrowUp/KeyX: if play: tryRotate; preventDefault (up scrolls). - ArrowDown: if play: soft immediate step; hold soft true. - Space: hard drop; preventDefault. - e.repeat guard for arrows? For left/right, native repeats would double with my DAS — I should ignore e.repeat for all handled keys and rely on custom repeat. Yes: if(e.repeat) return (after preventDefault? put guard early: if(e.repeat) { e.preventDefault(); return; } for handled keys — simpler: handle non-repeat only; also preventDefault on repeats to stop scrolling with down held... but if e.repeat with down held, we prevent default but ignore → custom soft handles it. OK: at top: if REPEATABLE codes include the key and e.repeat → preventDefault + return.) Held tracking keyup: clear hold; recompute dasDir from remaining. Note: when two dirs held, DAS uses latest? I'll track heldL/heldR with timestamps and dasDir = last-pressed wins: on press set dasDir to that dir; on release if released dir === dasDir, dasDir = other still held ? other : 0. Good. Restart: reset all state: board empty, score/lines/level reset, bag refill, spawn first piece, state 'play', syncUI. Ready state initial: I'll have initial state 'ready' where board shown empty + overlay "PRESS ENTER TO START". First spawn happens at start. start(): reset(); state='play'. reset(): score=0,lines=0,level=1,speed=intervalFor(1); bag=[]; board = empty; currentPiece=null; spawnNext() (fills current & next); dropAcc=0; lockAcc=0; clearT=0; fullRows=[]; syncUI. spawnNext(): current = next || pull; next = pull; position spawn; if collide → over. Also renderPreview. On lock: merge; sfx; current=null; compute clears; if clears: state='clear', clearT=0, sfxClear, shake=amp; else spawnNext() (state stays play). Hmm during 'clear' the next piece is waiting. finishClear → score/lines/level/speed updates; spawnNext; state='play'. gameOver(): state='over'; best update; sfxOver; syncUI (best). Render 'over': draw board? Yes with dim overlay + texts. Pause: overlay. Now write render carefully with logical coords and transforms. Canvas sizing: ```js const cvB=document.getElementById('board'); const DPR=Math.max(1,Math.min(2,devicePixelRatio||1)); cvB.width=W*CELL*DPR; cvB.height=H*CELL*DPR; const bctx=cvB.getContext('2d'); bctx.scale(DPR,DPR); ``` Set CSS in stylesheet: canvas#board{width:100%; aspect-ratio:1/2; display:block}. Stage width: 300px desktop. Shake: in render, if state==='clear': amp decay: shakeT decay by dt? I'm in render without dt... store shakeAmp, decays each frame by fixed amount (per-frame decay: amp*=0.88 each frame at 60fps — frame-rate dependent but acceptable; better: compute decay from delta via last render time). I'll do: in loop after computing dt: if(shakeAmp>0){ shakeAmp*=Math.pow(0.86? Let's use exponential per ms: shakeAmp *= Math.exp(-dt/90);} and set offset in render: translate((rand-0.5)*amp...). Apply inside render: bctx.save(); bctx.translate(ox,oy); draw; restore. Simpler: apply translate only to board content (whole). Fine. Random per frame gives jitter: ox=(Math.random()-.5)*shakeAmp*2. drawCell needs ctx param (board ctx vs preview ctx) — I'll implement generic function drawCellOn(ctx, px,py,s,color) with helpers shade cached. Colors precomputed map: for each key, {main, lite, dark}. Ghost drawing: for each filled cell of piece at ghostY: strokeStyle rgba of piece color? Need rgba from hex: helper hexToRgba(hex, a). Stroke width 1.5? Use 1.5 logical px? use 2 with roundRect r=3, alpha .5 stroke; plus fill alpha .06. Draw inset same as cells to align. Danger strip: draw before overlays. Preview: pctx on canvas 5×5 cells of 20? Logical 100x100: cell 20, center bbox: bw=(maxX-minX+1)*20 etc. offsets. DPR-scale too. CSS width 100px? Let canvas CSS width:100%; aspect 1; inside card centered. Card padding makes ~100px box. Draw next piece with mini cells (drawCellOn with s=20, radius 3). Draw preview even during clear (next known). During ready/over: preview shows upcoming? Ready: next exists after reset? reset() called on start only; at initial 'ready' before start, spawn pieces? I'll call reset() at load too (so board/preview populated) but state stays 'ready'; start() sets state='play'. So overlay "PRESS ENTER TO START" over populated board (empty anyway). Good. Score sync: function syncUI() sets textContents: score, best, lines, level, speed(ms), bar width, lastclear. Call after changes. Best storage: localStorage key 'blockfall-best'; try/catch (sandbox). Initialize 0 if parse fails. lastClear pop animation: CSS .pop { animation: pop .6s ease-out } @keyframes pop{0%{transform:translateY(-3px);color:var(--accent)}100%{...}}? Use animation that starts each retrigger via class re-add. Colors: from teal → normal. Fine. Now overlays text helper: ```js function overlayText(lines...)? function centered(txt, y, size, weight, color, tracking){ // manual tracking bctx.font = `${weight} ${size}px ${FONT_STACK}`; compute widths per char with spacing ``` Implement: ```js function textC(str, y, size, {weight=700, color='#e8ebf2', ls=0, alpha=1}={}){ bctx.font=`${weight} ${size}px ${MONO}`; bctx.fillStyle=color; bctx.textBaseline='alphabetic'; const chars=[...str]; const ws=chars.map(c=>bctx.measureText(c).width); const total=ws.reduce((a,b)=>a+b,0)+ls*(chars.length-1); let x=(W*CELL-total)/2; for(...){ bctx.fillText(ch, x, y); x+=w+ls; } } ``` MONO string: `"SF Mono","Cascadia Mono","Consolas",Menlo,monospace` — canvas font with commas fine. Blinking hint: alpha = .55+.35*Math.sin(now/450). Overlay dim: bctx.fillStyle='rgba(7,8,10,0.82)'; fillRect all. Then optionally a thin inner accent line? Keep text only. Ready overlay: "READY" small? Layout: big "BLOCKFALL"? Title already masthead; overlay: main "PRESS ENTER" 20px + hint "TO START" muted? Let me: textC('PRESS ENTER', 300? center y ~ H*CELL/2 - 8, 22), below muted 'START THE GAME' small? Simpler: line1 'READY' 40px weight800 ls 6? I'll do: 'BLOCKFALL' 26px at y=280? Actually canvas is 300x600 logical; center 300. Compose: y=280 'READY' 34px ls 8; y=330 'PRESS ENTER TO START' 13px muted alpha blink. Good. Pause: 'PAUSED' + 'P TO RESUME'. Over: 'GAME OVER' 34 ls 6 at 250; score line 'SCORE 12,340' 16px at 310; 'LINES 23 · LEVEL 3' 13 muted 340; 'PRESS R TO RESTART' blink 13 at 390. Number formatting in overlay: use toLocaleString. Also during play maybe show small current level marker? Panel covers. Sounds detail: ```js let AC=null, muted=false, master=null; function ac(){ if(!AC){ AC=new (window.AudioContext||window.webkitAudioContext)(); master=AC.createGain(); master.gain.value=.5; master.connect(AC.destination);} if(AC.state==='suspended') AC.resume(); return AC; } function tone(f, t0off, dur, {type='sine', vol=.2, to=null}={}){ if(muted) return; const c=ac(); const t=c.currentTime+t0off; const o=c.createOscillator(); o.type=type; o.frequency.setValueAtTime(f,t); if(to) o.frequency.exponentialRampToValueAtTime(to, t+dur); const g=c.createGain(); g.gain.setValueAtTime(0.0001? use set: g.gain.setValueAtTime(vol,t); g.gain.exponentialRampToValueAtTime(0.001, t+dur); o.connect(g); g.connect(master); o.start(t); o.stop(t+dur+.02); } ``` Wait gain start: setValueAtTime(vol, t) then exp ramp to 0.001 → click-free-ish (start at vol instantly causes click; add tiny ramp: g.gain.setValueAtTime(0,t); g.gain.linearRampToValueAtTime(vol, t+0.005); then exp decay). Fine. sfx = { rotate: ()=> tone(740,0,.05,{type:'triangle',vol:.12}), lock: ()=> { tone(140,0,.08,{type:'square',vol:.18,to:70}); tone(50? } keep: tone(120,0,.07,{type:'square',vol:.2}) + tone(60,0,.1,{type:'sine',vol:.25}) hard: tone(90,0,.1,{type:'square',vol:.25,to:45}) clear(n): const notes=[523.25,659.25,787.65? use scale: 523,659,787,1046]; for i=interval){ stepDown(); dropAcc-=interval; if blocked break; } where stepDown attempts y+1; if blocked → grounded (break). Grounded: lockAcc+=dt (cap at LOCK_MS+50). Also if piece grounded and player moves off ledge, unground: detect in stepDown? Handle each update: compute groundedNow = collide(y+1). If groundedNow: lockAcc+=dt; if lockAcc>LOCK_MS → lockPiece(). else: lockAcc=0? and gravity: dropAcc+=dt; while(dropAcc>=interval && !collide(y+1)){ y++; dropAcc-=interval; if(softHeld) score++? add per step; sync? score updates each frame cheap: I'll update DOM only when score changes: track in step and call syncUI (fine, 20/s calls ok). } and if(dropAcc>interval) dropAcc=interval? clamp. But grounded case should still allow soft/hard actions (they check collide). Down keydown immediate: stepDown manual: if(!collide(y+1)){y++; score++ if soft... dropAcc=0;}. If grounded, pressing down does nothing (waits lock). Optionally pressing down while grounded accelerates lock: lockAcc=LOCK_MS (instant lock on down press while grounded — common QoL). I'll implement: down keydown when grounded → lock immediately? That can cause accidental locks... Guideline does soft-lock on down when grounded? Many implementations lock. Hmm risk minor. I'll do: pressing down while grounded sets lockAcc to trigger soon (lockAcc = LOCK_MS - 100? ). Simplest: no accelerate; piece locks after delay anyway. Keep no. tryMove(dx): if(!collide(matrix,x+dx,y)){x+=dx; sfxMove? skip sound; if grounded reset lockAcc (with cap counter lockResets).} Also when moving, recompute grounded naturally. tryRotate(): m2=rotateCW(matrix); for kicks: if(!collide(m2, x+dx, y+dy)){ matrix=m2; x+=dx; y+=dy; sfx.rotate; if grounded reset lockAcc; break; }. Note: kicks with dy=-1 might push piece above top (y-1) with cells above 0 — fine. Hard drop: steps loop; if steps>0 score+=steps*2; lockPiece(); sfx.hard (call before merge? merge includes clear detect; order: sfx.hard then lockPiece which may sfx.lock — double thud; skip lock sfx when hard? I'll not sfx.lock on hard (pass flag). lockPiece(): merge into board; check over; clears detection; ... as planned. sfx.lock when no clears (soft thud). Also after lockPiece if no clears: spawnNext immediately (state stays 'play'). Spawn overlap → gameOver. Edge: spawnNext after lock while previous piece just merged at top rows — game over triggers, ok. Now writing the clear animation & removal with fullRows stored as array of row indices. finishClear: ```js const n=fullRows.length; const pts=[0,100,300,500,800][n]*level; score+=pts; lines+=n; const nl=Math.floor(lines/10)+1; if(nl>level){level=nl; speed=intervalFor(level); sfx.level(); lastSet? callout "LEVEL "+level? Clear callout already used for clear msg; show combined? I'll append level info: msg = `${nameFor(n)} +${pts}`; if leveled: msg += ` · LV ${level}`.} nameFor: ['','SINGLE','DOUBLE','TRIPLE','TETRIS']. lastClearShow(msg). syncUI(); // rebuild board const set=new Set(fullRows); const kept=[]; for(let r=0;rArray(W).fill(0)). Piece merge writes colors into board. Also collision function must handle matrix reference piece.matrix. One more: rotation for O (2×2): rotateCW works and result identical; no kick needed; but collision same → fine. I piece spawn x: bbox width 4 → x=3, y=-1 (minY=1 → y=-1): top filled row at y=0. Good. O: minX0,maxX1 → w=2 → x=4; y=-0 → top at 0. T etc: row0 has cell (T: [0,1,0]) minX=0? filled minX=0 (row1 col0), maxX=2 → w=3 → x=3; minY=0 → y=0. T spawn shows top cell row0, body row1 — standard. Hmm wait: x computed as Math.floor((W-(maxX-minX+1))/2)-minX. T: (10-3)/2=3.5→3; -0 →3. Piece occupies cols 3-5. Good. I: (10-4)/2=3; -0 →3, cols 3-6. Fine. O: (10-2)/2=4 → cols 4-5. Good. collide at spawn check: with y=-minY, top cells at row0 ok. Game over when spawn collides → also visually show the colliding piece? We set piece then over; render draws piece + overlay over dim; fine. Now HTML/CSS writing. Let me draft the CSS with care for a cohesive look. Colors: --bg:#0d0f12; --panel:#14161c; --panel2:#191c24; --line:#262a35; --line2:#31364a? keep: --line:#272c38; --ink:#e7eaf1; --muted:#7c8593; --dim:#515a68; --accent:#3fcfbd. Body bg: #0d0f12 flat. Maybe add subtle noise? skip. Masthead: ``` .masthead{display:flex; align-items:baseline; gap:14px; margin:0 2px 18px;} h1{font-size:15px; letter-spacing:.42em; font-weight:700; margin:0; color:var(--ink); transform? padding-left? } // "BLOCKFALL" with .42em tracking; trailing letter-space leaves right pad — set margin-right:-.42em to balance. .mark{...} two tiny squares: I'll make with spans: .mark{display:inline-flex; gap:3px} span 7x7 backgrounds accent & orange offset? Keep one: a 9px square accent + a 9px square translated? simple flexbox two squares different colors, second translated down 4px via translateY. Cute mini tetromino hint. Actually inline before title. .tag{color:var(--muted); font-size:11px; letter-spacing:.14em; margin-left:auto} ``` Stage: ``` .stage{flex:0 0 auto; width:300px;} .boardWrap{border:1px solid var(--line); background:#0b0d10; border-radius:10px; overflow:hidden? } canvas display block width 100% aspect 1/2. ``` Give canvas border-radius 8 + border 1px solid var(--line). Canvas paints bg so fine. Panel cards: ``` .panel{width:230px; display:flex; flex-direction:column; gap:12px} .card{background:var(--panel); border:1px solid var(--line); border-radius:10px; padding:12px 14px} .label{font-size:9.5px; letter-spacing:.22em; color:var(--muted); margin-bottom:8px} ``` Score card: value font-size 24px letter-spacing .04em? tabular. Row BEST: flex space-between small. Progress card: header row with label + speed right aligned muted. values row: three columns? LINES and LEVEL side by side: `.duo{display:grid; grid-template-columns:1fr 1fr; gap:8px}` each: small label + value 18px. Bar below spanning both with margin-top 10. Last clear card: label + value (`.flash`). Controls card rows: `.krow{display:flex; justify-content:space-between; align-items:center; padding:5px 0; border-top? use + not separators? subtle: no borders, spacing} .krow .what{font-size:11px; color:var(--muted); letter-spacing:.08em}` chips. Button chip: `` styled as kbd but hover invert. Row structure: what='SOUND', right: [chip M][chip toggle-state]? Simpler: one row: left 'SOUND'; right: `` toggling text 'M OFF'. Make it look like a keycap but interactive (cursor:pointer, hover border accent). Good. Footer under stage? Small line under masthead? Add `.foot` under .game: muted 10px: "SPACE hard-drops · hold ↓ to soft-drop · stack to the top ends the run". Maybe unnecessary; include one-line footer with left "rotate respects walls & stack" right "v1"? Keep minimal: skip footer, controls card explains. Add tiny line under controls card: "R restarts any time." as row in controls card. Fine: include row RESTART R anytime. Responsive: ``` @media (max-width:640px){ .game{flex-direction:column; align-items:center} .panel{width:300px; max-width:100%} .masthead{width:100%;} } ``` Stage width on small: width: min(300px, 92vw)? .stage{width:300px} → on narrow screens 300 might overflow with padding 20*2+? 300+40=340 fits most phones (375). Use .stage{width:min(300px, calc(100vw - 40px))}? CSS: width: clamp(220px, 100%, 300px)? I'll set .stage{width:300px; max-width:calc(100vw - 40px)} and canvas width 100% aspect-ratio keeps scaling. Good. Preview canvas: card with label; canvas width 100%? fixed 100px: `#preview{width:100px; height:100px; display:block; margin:2px auto 0}` logical 100. Draw bg transparent? Canvas transparent shows card bg; I'll draw faint border box? Draw nothing but piece; add subtle inner border via CSS: border:1px solid var(--line); border-radius:8; background:#0b0d10. Set canvas background via CSS #0b0d10 + border. Then draw piece. DPR handle: cvP.width=100*DPR etc; pctx.scale(DPR,DPR). Actually preview box 100px square within card width ~230-28=202? Center via margin auto. Looks fine; maybe make it wider card? preview box small — fine. Hmm: Card NEXT could be horizontal: label left, box right to save vertical space? Vertical stack is fine but panel tall... Panel height vs stage (600+pad). Cards total: next(~130) + score(~90) + progress(~110) + clear(~70) + controls(~200) ≈ 600+. Roughly matches 600px stage height. Good; align panel content top, controls at bottom? Use .panel{justify-content? natural} plus maybe margin-top:auto on controls card to pin bottom: .panel .controls{margin-top:auto}? gap handles; add margin-top:auto to controls card so panel bottom aligns with stage bottom. Nice. Score card could be merged with progress to save space; keep separate as designed. Now the JS in full. Let me write it carefully. ```js 'use strict'; const W=10, H=20, CELL=30, FW=W*CELL, FH=H*CELL; const DAS=170, ARR=45, SOFT=45, LOCK_MS=500, CLEAR_MS=280; const KEYS=['I','J','L','O','S','T','Z']; const PIECES={ I:{c:'#3fcfbd',m:[[0,0,0,0],[1,1,1,1],[0,0,0,0],[0,0,0,0]]}, J:{c:'#5c8cf0',m:[[1,0,0],[1,1,1],[0,0,0]]}, L:{c:'#ef913c',m:[[0,0,1],[1,1,1],[0,0,0]]}, O:{c:'#e6b73c',m:[[1,1],[1,1]]}, S:{c:'#68d06a',m:[[0,1,1],[1,1,0],[0,0,0]]}, T:{c:'#a765e6',m:[[0,1,0],[1,1,1],[0,0,0]]}, Z:{c:'#e26363',m:[[1,1,0],[0,1,1],[0,0,0]]} }; ``` shade util: ```js function shade(hex,amt){ const n=parseInt(hex.slice(1),16), r=(n>>16)&255,g=(n>>8)&255,b=n&255; const t=amt<0?0:255, p=Math.abs(amt)/100? standard: c=Math.round((t-c*v? use mix: const k=amt/100; return rgb(mix each channel toward t by |k|) } ``` Simplify: ```js function shade(hex,k){ // k in [-1..1] const n=parseInt(hex.slice(1),16); let r=(n>>16)&255,g=(n>>8)&255,b=n&255; const t=k<0?0:255, a=Math.abs(k); r=Math.round(r+(t-r)*a); g=Math.round(g+(t-g)*a); b=Math.round(b+(t-b)*a); return `rgb(${r},${g},${b})`; } ``` Precompute PALS[key]={main, lite:shade(c,.45), dark:shade(c,-.45)}. rgba helper: ```js function rgba(hex,a){ const n=parseInt(hex.slice(1),16); return `rgba(${(n>>16)&255},${(n>>8)&255},${n&255},${a})`; } ``` roundRect: ```js function rrect(c,x,y,w,h,r){ c.beginPath(); c.moveTo(x+r,y); c.arcTo(x+w,y,x+w,y+h,r); c.arcTo(x+w,y+h,x,y+h,r); c.arcTo(x,y+h,x,y,r); c.arcTo(x,y,x+w,y,r); c.closePath(); } ``` Careful arcTo sequence standard. drawCell(c,px,py,s,pal): ```js const inset=1, r=Math.max(2,s*.09); // dark base (creates bottom-right bevel) c.fillStyle=pal.dark; rrect(c,px+1,py+1,s-2,s-2,r); c.fill(); // main c.fillStyle=pal.main; rrect(c,px+1,py+1,s-4,s-4,r*.8? use Math.max(1.5,r-1)); c.fill(); // lite top-left bevel c.fillStyle=pal.lite? with alpha: use globalAlpha .5? lite color already lighter; draw strips: c.globalAlpha=.55; c.fillStyle=pal.lite; c.fillRect(px+2.5,py+2.5,s-8,2.5? Use thin rects: top strip (px+2.5, py+2.5, s-9, 2) and left (px+2.5, py+2.5, 2, s-9); c.globalAlpha=1; ``` Hmm let me reconsider widths: main rect inset dark by 2 → bevel 2px dark at bottom/right. lite strips inside main starting 2? positions: main spans px+1..px+s-4 (w s-4? Wait: dark rect w=s-2 at px+1; main rect w=s-4? That leaves dark band 2px at right/bottom (from s-4 to s-2) — but top/left edges: main and dark share origin px+1, so dark not visible top/left — but dark base under main... top-left edges show main directly against bg with no bevel — plus lite strips drawn at top-left inside. Good. main rect: x=px+1,y=py+1,w=s-4,h=s-4? Then bottom-right dark band thickness 2px? dark extends to px+s-1 (x+w=px+1+s-2) and main to px+1+s-4=px+s-3: band from px+s-3 to px+s-1 = 2px. Good. But visually dark band at right ~2px and bottom 2px: ok. lite strips: within main: top strip: rect(px+2.5, py+2.5, (s-4)-5= s-9? Let me not over-tune; use: strip len = s-8. top strip rect(px+2.5,py+2.5,s-8,2); left strip rect(px+2.5,py+2.5,2,s-8). alpha .5. For s=30: len 22 — leaves 2px right gap inside main... rect width s-8=22 from px+2.5 to px+24.5; main right edge at px+1+s-4=px+27; fine. But wait main rounded corners r smaller — strips at corners may poke outside main rounded corner slightly near top-left; strip starts at +2.5 with corner radius ~2.5 → mostly inside; minor overlap acceptable (drawn over dark? strip drawn after main, over dark corner region of dark rect? The dark corner at top-left is covered by main? Both rounded same origin; dark visible only bottom/right as computed. The strip near top-left corner sits on main — rounded corner of main at r*0.8≈2.2; strip corner square may extend past main's rounded corner by <0.5px → negligible over dark? dark rect corner radius r=2.7... tiny overlap with dark corner region; visually negligible at alpha .5 lite over dark. ok. Ghost draw: ```js function drawGhost(c,px,py,s,color){ c.strokeStyle=rgba(color,.45); c.lineWidth=1.5? 1; rrect(c,px+2,py+2,s-4,s-4,r); c.stroke(); c.fillStyle? faint fill rgba(color,.07) fill first then stroke } ``` Draw fill then stroke. Preview mini cells same drawCell with s=22? Use 20. Board render: ```js function render(now){ // shake offset let ox=0, oy=0; if(shakeAmp>0.3){ ox=(Math.random()-.5)*shakeAmp*2; oy=(Math.random()-.5)*shakeAmp*2; } bctx.save(); bctx.translate(ox,oy); // bg bctx.fillStyle='#0b0d10'; bctx.fillRect(-4,-4? cover whole incl shake bleed: fillRect(0- ? fill (0,0,FW,FH) then shake reveals gaps at edges... fill slightly larger: fillRect(-6,-6,FW+12,FH+12). Good. // grid bctx.strokeStyle='rgba(255,255,255,0.055)'; bctx.lineWidth=1; bctx.beginPath(); for(let i=1;ipiece.y) draw ghost cells at y=g (skip if equal? if g===piece.y skip? drawing ghost overlapping piece invisible fine; draw anyway harmless. Draw ghost first, then piece over). piece cells: drawCell at (x+c)*CELL, (y+r)*CELL. ``` ghostY(): let yy=piece.y; while(!collide(piece.matrix, piece.x, yy+1)) yy++; return yy. Danger: ```js let top=H; for r: if(rowHasCell) {top=r;break}; if(top<=4){ pulse; bctx.fillStyle=`rgba(226,70,70,${0.05+0.05*(0.5+0.5*Math.sin(now/300))})`? alpha .04..0.09; fillRect(0,0,FW,(5)*CELL)? cover rows 0..top? cover rows 0..4 only if top<=4? cover rows 0..3: fillRect(0,0,FW,4*CELL). Also maybe thin red line at bottom of zone? skip.} ``` Only show when top<=3? use threshold 3 (rows 0-3 free-ish). If stack at row3 (height 17) it's risky; show strip over rows 0..3. ok. Overlays: ```js if(state!=='play'&&state!=='clear'){ bctx.fillStyle='rgba(6,7,9,'+(state==='over'?0.86:0.8)+')'; bctx.fillRect(0,0,FW,FH); if(state==='ready'){ textC('READY', 282? Let me place: title small? Big 'READY' 36px ls 10 at y=286; sub 'PRESS ENTER TO START' 13 muted blink at 326. } if(state==='pause'){ 'PAUSED' 36 ls10 286; 'P TO RESUME' 13 blink 326 } if(state==='over'){ 'GAME OVER' 34 ls 8 at 262? then `SCORE ${fmt(score)}` 17 at 318; `LINES ${lines} · LEVEL ${level}` 13 muted at 348; 'PRESS R TO RESTART' 13 blink at 392 } } bctx.restore(); ``` Also during ready state board empty → looks plain; fine. textC helper as planned with manual tracking; color param. fmt(n)=n.toLocaleString('en-US'). Now update(dt): ```js function update(dt){ // DAS if(dasDir){ dasT+=dt; if(dasT>DAS){ arrAcc+=dt; while(arrAcc>=ARR){ tryMove(dasDir); arrAcc-=ARR; } } } else { arrAcc=ARR? reset arrAcc=0; dasT=0? handled on press } // gravity const iv = softHeld? SOFT : speed; if(piece && !collide(piece.matrix, piece.x, piece.y+1)){ if(piece.grounded){ piece.grounded=false; lockAcc=0; dropAcc=Math.min(dropAcc, iv); } dropAcc+=dt; while(dropAcc>=iv){ if(!collide(...y+1)){ piece.y++; if(softHeld){score++; uiScore();} dropAcc-=iv; } else { dropAcc=iv; break; } } } else { piece.grounded=true; dropAcc=0? keep 0; lockAcc+=dt; if(lockAcc>=LOCK_MS) lockPiece(false); } } ``` Hmm grounded flag: maintain piece.grounded boolean; compute each update. When grounded and gravity: dropAcc reset 0 to avoid burst. When unground (e.g., after kick lift or piece moved off edge) reset. Also when player rotates to unground, next update detects !collide → grounded=false. Potential bug: tryMove changes x only; grounded status recompute each update — fine. Also when state==='clear', piece null; update skipped entirely (only run when play). And DAS keys during clear: ignore (update not called, keydown tryMove guarded by state==='play' and piece exists). On finishClear piece exists. tryMove: ```js function tryMove(dx){ if(!piece) return; if(!collide(piece.matrix,piece.x+dx,piece.y)){ piece.x+=dx; if(piece.grounded && lockResets<12){ lockAcc=0; lockResets++; } } } ``` lockResets reset on new piece spawn & on dropping? Reset lockResets when piece.y increments (falls) — set piece.lockResets? Put on piece object: piece.lockResets=0 at spawn; reset to 0 whenever y++ or rotate success that changes grounded to false? Simple: on spawn 0; on any successful gravity fall 0; cap 12. Fine. tryRotate: ```js function tryRotate(){ if(!piece) return; const m2=rotCW(piece.matrix); const KICKS=[[0,0],[-1,0],[1,0],[-2,0],[2,0],[0,-1],[-1,-1],[1,-1],[0,-2]]; for(const [dx,dy] of KICKS){ if(!collide(m2,piece.x+dx,piece.y+dy)){ piece.matrix=m2; piece.x+=dx; piece.y+=dy; sfx.rotate(); if(piece.grounded && piece.lockResets<12){lockAcc=0; piece.lockResets++;} return; } } } ``` Note: after kick lift, grounded recompute next update; lockAcc reset happened if it was grounded — but if kicked up, piece ungrounded next update sets grounded=false anyway with lockAcc=0 path. ok. collide(m,x,y): ```js function collide(m,x,y){ for(let r=0;r=W||by>=H) return true; if(by>=0&&board[by][bx]) return true; } } return false; } ``` rotCW as derived. merge/lock: ```js function lockPiece(hard){ let above=false; for cells: const by=piece.y+r, bx=piece.x+c; if(by>=0) board[by][bx]=piece.key; else above=true; if(above){ gameOver(); return; } piece=null; lockAcc=0; dropAcc=0; const full=[]; for(r) if(board[r].every(v=>v)) full.push(r); if(full.length){ fullRows=full; clearT=0; shakeAmp=4+full.length*1.6? amp: 3+n*1.5; state='clear'; sfx.clear(full.length); } else { if(!hard) sfx.lock(); spawnNext(); } } ``` Wait if above true → gameOver, but piece merged partially? Cells above top not merged (can't be drawn); cells at by>=0 merged; then game over — ok. Hmm also: hard drop into above? If piece hard-dropped with cells above 0 possible after kicks — handled. spawnNext(): ```js function spawnNext(){ current=nextPiece; nextPiece=pullBag(); place(current); renderPreview(); } function place(p){ // p = {key, color, matrix copy} const m=p.matrix; let minX=9,minY=9,maxX=-1; scan; p.x=Math.floor((W-(maxX-minX+1))/2)-minX; p.y=-minY; p.grounded=false; p.lockResets=0; if(collide(m,p.x,p.y)){ gameOver(); } } ``` pullBag: ```js function pullBag(){ if(!bag.length){ bag=KEYS.slice(); shuffle(bag); } const k=bag.pop(); const d=PIECES[k]; return { key:k, color:d.c, matrix:d.m.map(r=>r.slice()) }; } ``` Wait spawnNext: current becomes old nextPiece; but old nextPiece matrix may have been untouched (fresh) — but if we reuse the same object and later rotate mutates matrix... it becomes current piece and mutations fine (fresh clone created at pull). But when we set current=nextPiece, then pull new next. Current object reused fine. At reset: nextPiece=pullBag(); spawnNext()? spawnNext sets current=nextPiece then pulls new next. So reset: nextPiece=null? Just call: nextPiece=pullBag(); spawnNext(); → current = first, next = second. Good. shuffle: Fisher-Yates with Math.random. gameOver(): ```js function gameOver(){ state='over'; if(score>best){best=score; saveBest(); } uiAll(); sfx.over(); } ``` Note: gameOver called during update loop or keydown; render handles overlay. Also update loop must not continue physics when over (state check). start/reset: ```js function reset(){ board=Array.from({length:H},()=>Array(W).fill(0)); score=0; lines=0; level=1; speed=intervalFor(1); bag=[]; nextPiece=null; dropAcc=0; lockAcc=0; fullRows=[]; clearT=0; shakeAmp=0; lastClearEl? set '—'; nextPiece=pullBag(); spawnNext(); uiAll(); } function start(){ reset(); state='play'; } ``` Wait spawnNext uses current=nextPiece; nextPiece=pullBag() — with nextPiece freshly pulled then reassigned: sequence: nextPiece=pullBag(); spawnNext(): current=nextPiece (first), nextPiece=pullBag() (second). Good. restart on R: start(). Line clear scoring name: NAME=[null,'SINGLE','DOUBLE','TRIPLE','TETRIS']. lastClear show: ```js function flashClear(msg){ clearEl.textContent=msg; clearEl.classList.remove('pop'); void clearEl.offsetWidth; clearEl.classList.add('pop'); } ``` uiAll / uiScore: update DOM fields: scoreEl.textContent=fmt(score); bestEl=fmt(best); linesEl=lines; levelEl=level; speedEl=speed+' MS'; bar width: ((lines%10)*10)+'%'? When lines%10===0 after level-up, bar 0. Also during play partial. Set bar fill width (lines%10)/10*100. Wait: level-up happens only on clear (lines add multiples). lines%10 goes 1..9 then 0. Bar shows progress. fine. Level card speed display: `${speed} ms`. Muted. Best load: ```js let best=0; try{ best=parseInt(localStorage.getItem('blockfall-best')||'0',10)||0; }catch(e){} saveBest: try{ localStorage.setItem(...)}catch(e){} ``` Keydown handler: ```js document.addEventListener('keydown', e=>{ const c=e.code? use e.code for reliability (Space). const code=e.code; const game=state==='play'; if(code==='Enter'){ if(state==='ready'||state==='over') start(); e.preventDefault(); return; } if(code==='KeyR'){ start(); e.preventDefault(); return; } // restart anytime if(code==='KeyP'){ if(state==='play'){ state='pause'; } else if(state==='pause'){ state='play'; lastT? dt clamp handles } e.preventDefault(); return; } if(code==='KeyM'||code==='Audio... ' use KeyM: toggleSound(); e.preventDefault(); return; if(['ArrowLeft','ArrowRight','ArrowUp','ArrowDown','Space'].includes(code)) e.preventDefault(); else return; if(e.repeat) return; if(!game) return; switch(code){ case 'ArrowLeft': heldL=true; dasDir=-1; dasT=0; arrAcc=ARR? set arrAcc=0; tryMove(-1); break; case 'ArrowRight': heldR=true; dasDir=1; dasT=0; tryMove(1); break; case 'ArrowUp': case 'KeyX': tryRotate(); break; case 'ArrowDown': heldDown=true; softStep(); break; // softStep: immediate case 'Space': hardDrop(); break; } }); ``` Note KeyX handled in switch? I put KeyX with ArrowUp — but KeyX not in the preventDefault list; add 'KeyX' to handled list & preventDefault. Also keydown for KeyX when not play → return early; ok. Wait structure: I check includes(code) after the special keys; if code==='KeyX' not included → returns before rotation. Add 'KeyX' to list. Also note Enter/R/P/M also need preventDefault? Enter on focused button could trigger click; preventDefault fine. Also for repeat guard: e.repeat for arrows/space ignored (custom repeat); for Up/X repeat ignored. keyup: ```js document.addEventListener('keyup', e=>{ const code=e.code; if(code==='ArrowLeft'){ heldL=false; if(dasDir===-1){ dasDir=heldR?1:0; dasT=0? keep dasT? if switching, reset dasT? Keep dasT (already charged)? If R held and was earlier, switching dir should get DAS delay fresh: dasT=0; arrAcc=0;} } similar right; if(code==='ArrowDown') heldDown=false; }); ``` Also on blur: clear holds & pause if playing: ```js window.addEventListener('blur', ()=>{ heldL=heldR=heldDown=false; dasDir=0; if(state==='play') state='pause'; }); ``` softStep(): ```js function softStep(){ if(!piece) return; if(!collide(piece.matrix,piece.x,piece.y+1)){ piece.y++; score+=1? score+=1; uiScore(); dropAcc=0; if(piece.grounded){piece.grounded=false; piece.lockResets=0;} } } ``` Hmm scoring +1 per soft step — yes. hardDrop(): ```js function hardDrop(){ if(!piece) return; let n=0; while(!collide(piece.matrix,piece.x,piece.y+1)){ piece.y++; n++; } if(n>0){ score+=n*2; } sfx.hard(); lockPiece(true); uiScore(); } ``` Note lockPiece(true) sets state maybe 'clear'. If game over inside, fine. One issue: sfx.hard always plays even n=0 (piece already grounded) — fine thud. update loop DAS arrAcc reset: on press set arrAcc=ARR so that first repeat after DAS fires immediately? Let me define: arrAcc counts toward ARR; on press: dasT=0, arrAcc=0. In update: if dasT>DAS: arrAcc+=dt; while(arrAcc>=ARR){move; arrAcc-=ARR}. First repeat occurs at dasT>DAS + ARR ms. That's 215ms first repeat — standard. fine. Also dasT resets each press; if user holds left while tapping right... handled via dasDir logic === answer so far ===