Tetris · deepseek-v4.1-flash

Let me build the Tetris game in index.html. Then use the browser tool to inspect.

Let me write a complete implementation.

Now let me run the browser and inspect. I'll reload, inspect DOM, screenshot, then do representative checks.

The browser starts on index.html presumably. Let me reload.

The first piece is S (green). Next is I. Looks good. Note the S piece spawns with cells [[1,0],[2,0],[0,1],[1,1]], at x=3, y=-1. So cell rows: y=-1 cells not drawn (1,0 at y=0? wait). Let me check: S rot 0 shape [[1,0],[2,0],[0,1],[1,1]], piece at x=3,y=-1. Cells: (4,-1),(5,-1),(3,0),(4,0). Drawn cells at y>=0: (3,0) and (4,0) — two green blocks. That matches the screenshot. Good.

Now test move/rotate/hard-drop. Let me click on canvas to focus, then send keys. Actually key events go to document. Let me use the browser key action. The key tool likely sends key to focused element. Let me click the canvas first.

Let me do: press ArrowRight, ArrowUp, then Space. Then inspect screenshot.

Interesting — the piece already dropped a bit due to gravity, and now the S fully drawn (all 4 cells visible). Now send ArrowRight, ArrowUp, Space.

Hmm. The keys seem to have moved/rotated the piece, but the hard-drop Space did not happen? Wait, look: frame 1 after ArrowRight moved piece to right. Frame 2 after ArrowUp rotated — S rotated. Frame 3 after Space — hmm, the third screenshot shows the S piece near the bottom, and the next preview changed to T, and board top shows a settled row of I blocks? Wait no.

Let me analyze third screenshot: Top of board has 4 cyan blocks (I) in a row at row 0. Next preview shows T (purple). The green S is near bottom mid. Score 0. So it appears the hard drop happened for... hmm. Wait, actually the order might be off. The three key calls happened sequentially, each returning a screenshot. The last screenshot is after Space. But it shows a cyan I piece at the top settled and green S still falling near bottom. That's odd.

Wait — maybe the screenshots are from earlier frames/lag. Actually each browser call returns a screenshot of that moment. Let me reconsider: The first call ArrowRight returned screenshot showing S at center-right. Second ArrowUp returned screenshot showing S rotated (vertical-ish). Third Space returned screenshot showing... S still near bottom and a cyan I at top, next=T.

Hmm, that doesn't line up. Actually maybe the Space triggered a hard drop of S, it locked, then spawn happened... but next piece shown is T, and I appeared at top? No, next preview before was I, so after hard drop, next becomes I spawns and preview becomes... but preview shows T. So maybe two pieces dropped?

Actually wait: gravity. During the ~ between frames, the piece falls. Let me think about timing: I sent click then three keys. Between each browser call there's real time (maybe seconds). Gravity at 800ms. The click screenshot showed S with all cells at row ~1-2. After ArrowRight screenshot, S still at similar height. After ArrowUp, S rotated and moved down a bit. After Space, hard drop: S locked at bottom. Then I spawns (from next) and next preview becomes T. Then because time passed between the Space screenshot and the screenshot capture, the I piece may have... but I appears at top row 0, not falling. Hmm, and green S appears near bottom still? That's just the locked S at the bottom — yes! The green S near bottom IS the locked piece. And cyan I at top is the new falling piece. That all makes sense. 

Wait but the locked S near bottom — is it at the bottom? Screenshot shows it at around y=540-740px of 600px canvas region... board starts at y=0 in canvas. The green blocks are near bottom. Good. And score still 0 since no lines cleared. Next preview = T. Great, hard drop worked, new piece spawned, preview advanced.

But wait, why is the I at row 0 fully horizontal and not falling? Because only a moment passed. Fine.

Actually hold on, one issue: the S locked shape at bottom looks like it's floating? It's at bottom rows. Fine.

So the verify requirement works. Now pause/resume and restart. Let me press P, inspect overlay, press P again, then R and check score/lines/level reset.

But note the I piece is at top and might lock. Doesn't matter. Let me test.

Pause overlay shows, button says Resume. The I piece fell to mid-left. Good. Now resume and restart.

Resume worked (overlay gone, button "Pause", piece falling). Restart reset the board: new S piece at top, Next = I, score 0, lines 0, level 1. 

Now let me verify line-clearing scoring. That's harder to test via random play. I can test programmatically by injecting a script through browser? The browser tool only supports click/key/type/drag/scroll. I can't easily run JS. But I could temporarily expose functions or use the inspect. Alternatively I can reason about code correctness.

Let me double check clearLines logic. Loop y from ROWS-1 down. If full, splice(y,1), unshift empty row, then y++ (so next iteration y-- makes it same y again). Good.

Score points table [0,100,300,500,800][cleared]*level. Good. Level every 10 lines. dropInterval updated.

One concern: In `spawn()`, piece = nextPiece || makePiece(nextType()); nextPiece = makePiece(nextType()); This means at reset: nextPiece = makePiece(nextType()); then spawn() sets piece = nextPiece (first type), nextPiece = new. Good.

The gameOver check on spawn: if collides, it tries piece.y -=1 then if collides endGame. But `piece.y -=1` then collides, then `piece.y +=1; endGame()`. Okay. But if the first collides test is false, fine.

Potential bug: after endGame, drawNext() called. fine. But draw() not called after endGame in spawn; in lock() we call draw() after spawn(). Good.

Another concern: hard drop with cells above top (y<0) — when locking, only cells y>=0 stored. Fine.

Rotation: no wall kicks; reject if collides. Good.

Let me verify that rotation of I near top works. Fine.

Testing line clear: I could simulate by opening devtools? Not available. Let me consider temporarily adding a test hook, but that would pollute. Actually I can add a hidden global API `window.__tetris` exposing board manipulation for test, then remove. But time budget. The logic is straightforward. Let me instead do a quick automated test by creating a temporary separate HTML? No, that doesn't test index.

Actually I can use the browser's type action? No.

Alternative: I can add a small debug hook only in a copy, not the final. But final must be index.html. I could temporarily edit index.html to expose hooks, test, then revert. That's feasible.

But maybe simpler: write a small Node script that loads the script portion? The code is in an IIFE with DOM deps. Hard.

Let me just temporarily expose a hook. Actually, I can test clear via game by hard-dropping many pieces to fill a row — unreliable.

Let me add `window.__t = {board:..., ...}` temporarily. Actually the functions reference closure vars; I can expose a function to set board. Let me do it quick: add before `reset();` a line `window.__test = { getBoard: function(){return board;}, setRow: function(y,type){ for(var x=0;x<COLS;x++) board[y][x]=type; }, clearLines: clearLines, getState: function(){return {score:score,lines:lines,level:level,gameOver:gameOver};}, lock: lock, hardDrop: hardDrop };`

Then via browser... but I can't call JS through the browser tool. There's no evaluate action. Hmm. The browser tool actions are limited. So exposing a hook is useless without a way to run JS.

Could I trigger it through keyboard by making a cheat key? I could temporarily bind a key to fill a row. Then press it, then hard drop, then check. Then remove the cheat. That works.

Let me add temporarily a key handler for "t" that fills bottom row except one column, and repeatedly. Actually to clear a line: fill bottom row entirely except one cell, then drop a piece into it. Simpler: cheat key that fills bottom row fully and calls clearLines directly. Then check score increments. That tests clearLines scoring.

Let me add temporary cheat: on key "1" fill bottom row and clearLines; "2" fill two rows; etc. Then revert. Let me do it.

Actually, I can test without keyboard by just trusting. But the task says inspect representative checks. Let me do the cheat test to be safe.

I'll temporarily add to keydown handler before gameOver check:
```
if (k === "9") { for (var xx=0;xx<COLS;xx++){board[ROWS-1][xx]="I";} clearLines(); draw(); updateHUD(); return; }
```
Wait clearLines already calls updateHUD. Need draw after. Let me add.

Then press 9 and inspect score. Then press 9 four times maybe. Let me add and test.

Now press 9 once → should score 100, lines 1. Then press 9 multiple times to reach level up. Let me press 9 ten times total and inspect. Actually each press adds a line. After 10 lines level becomes 2. Let me press 9 nine more times. But send key action repeatedly.

Let me first press 9 once and inspect, then press it 9 more.

Score 100, lines 1. Correct. Now press 9 nine more times to reach lines 10, level 2. Score would be 100 (level1) + 9*100 = 1000? Wait first at level1=100. Then next 9 clears at level1 too until 10th line. Score = 10*100 = 1000. Level becomes 2. Let me send 9 nine times. Multiple key calls in one block.

Line clearing works: score increments 100/line at level 1, and at 10 lines level becomes 2. Note score 1000 at lines 10, level 2. 

Now I need to test multi-line scoring (300/500/800). Let me add test for 4 rows at once. I could send a cheat key "8" that fills 4 bottom rows. Let me extend the cheat. Actually let me just modify cheat to fill N rows based on key. But time. The formula uses table; single-line verified. Multi-line is same code path with cleared count. I'm fairly confident.

But wait — there's a subtle bug: when clearing multiple adjacent full rows, after splice(y,1) and unshift, then y++ causes recheck of same y. That's correct. But if 4 rows full, they'd all be cleared. Good.

Actually let me quickly test 4-line clear with another cheat key. I'll change the cheat to key "8" fills bottom 4 rows. Let me edit.

Actually, I want to also test Game Over. That requires filling the board. Hard via keyboard but could use cheat to fill top rows. Let me add cheats: "8" fills bottom 4 rows then clearLines (tests 800), and maybe not necessary. Game over test: hard to trigger quickly. I could make cheat "0" fill the whole board and spawn to force game over. But the current piece already exists. Filling all rows then hard drop will collide with next spawn? Actually spawn happens after lock; board already full, so endGame. Let me test that too.

Let me edit the cheat line to handle multiple keys.

Now press "8" for four-line clear. Expected score 800, lines 4, level 1. Then press "0" for game over. Let me do 8 first.

Four-line clear gives 800 points, lines 4, level 1. Correct.

Now test game over with "0".

Whoa, score became NaN, lines 24, level 3. That's a bug! Wait, the board only shows 4 cyan at top. Hmm. But score NaN indicates a real bug in clearLines. Let me think.

The cheat "0" filled all 20 rows full, then hardDrop. hardDrop with piece: it's already at top; while loop checks collision with y+1; board is full so collides immediately, no move, then lock(). lock writes piece cells (overwriting), then clearLines(). clearLines should clear... wait board was entirely full, 20 rows all full. So clearLines loops and clears all 20 rows → cleared=20. points = [0,100,300,500,800][20] = undefined * level = NaN. That's why NaN! That's a test artifact: clearing 20 rows isn't possible in real gameplay (max 4). So this is not a real bug.

But lines became 24 (4 from before + 20). And level 3. So game over didn't trigger? Because after clearing all 20 rows, board empty, then spawn succeeds. So game over not triggered. Right.

So the NaN is from my unrealistic cheat clearing 20 rows at once. Not a real gameplay scenario. But wait — is it truly impossible? In real Tetris, max 4 rows can be cleared at once. So the points table is fine.

However, I should test game over more realistically. But it's hard. Let me instead just fill only the top row(s) and ensure spawn collision. Actually game over occurs when a new piece can't spawn. I can fill the board except keep it so after lock pieces stack to top. That's manual.

Alternative: game over is triggered in spawn() when collides. I can test by cheat: fill rows 0 and 1 completely (top two rows) but leave rest empty, then force a lock/spawn. But piece is at top; hardDrop would drop piece to bottom, clearLines maybe none, then spawn next at top → collides with full top rows → game over. But only if rows 0,1 stay full after lock. Since piece drops to bottom, top rows remain full. Let's do cheat that fills top 2 rows only, then hardDrop current piece (which is I at top). The I piece is currently occupying top row. Filling rows 0,1 then hardDrop: it drops to bottom, locks, spawn → collides at rows 0-1 → game over. 

Let me change cheat "0" to fill only top 2 rows. Actually simpler: modify cheat on the fly. Let me edit.

But also, more important: I should ensure NaN can't happen due to something else. In real game cleared is 1..4. Fine.

Let me update cheat to test game over properly. Change "0" handler to fill rows 0 and 1.

Interesting! Instead of game over, it scored 300, lines 2. Because I filled rows 0 and 1 while the O piece was at rows 0-1. The hardDrop dropped the O to the bottom, then clearLines cleared... wait rows 0,1 full (I filled them) AND after lock the top rows still full? No: The O piece was occupying rows 0,1 before I filled. I set rows 0,1 to I, overwriting. Then hardDrop moves O down to bottom and locks. Rows 0,1 remain full → clearLines clears 2 rows → score 300, lines 2. Then spawn succeeds (board empty). Right, so no game over.

I need to make the top rows full AND not clearable. The problem: filling full rows always clears. To force game over, I need a board where the new piece can't spawn but no full line clears. E.g., fill rows 0 and 1 except leave one column empty, with the stack. If row 0 has a gap, it won't clear. New piece spawns in columns 3-6, so leave gap at column 9 (far right). Then spawn collides because rows 0-1 have blocks in spawn columns. No lines clear.

But the active piece: hardDrop drops it to bottom and locks at bottom. Rows 0,1 remain with gap at col9 → no clear. Then spawn next → collides → game over.

Let me change cheat: fill rows 0,1 for columns 0..8 (leave column 9 empty). Then hardDrop. Actually the current piece occupies cells at top; dropping it leaves rows 0,1 as filled (cols 0-8). Good.

Wait but hardDrop while board rows 0,1 filled: the piece is currently at top. Does it collide at its current position? When I set board cells, I overwrite where the piece is, but collides checks board occupancy for the piece's cells. After filling rows 0,1, the piece at rows 0,1 now overlaps board → but hardDrop's loop starts testing y+1; at y+1 maybe also occupied. It will lock in place if collision below. Actually the piece is at y such that its cells are rows 0-1. Test y+1: cells row 1-2, row1 occupied → collide, break. So lock() writes piece over rows 0-1, then clearLines: rows 0,1 full (cols0-8 plus piece) — with gap at col9, not full. Good. Then spawn → collides → game over.

But careful: the O piece occupies cols 4,5 rows 0,1. Filling rows0-1 cols0-8 already includes those. Fine.

Let me update cheat to leave col9 empty.

Hmm, it didn't game over. Board shows rows 0,1 filled except col9 (empty). Score 0. But no new piece? The active piece seems gone (no falling piece?) and Next still shows Z (red). Wait the hardDrop locked the piece (J blue) into top rows. Then spawn: nextPiece was Z? Actually let me think. Board top rows show cyan (I fill) and blue (J piece). Board rows 0-1 filled cols 0-8. The active piece was J (blue), locked at top. next preview shows Z. So spawn of Z at top... it should collide with rows 0-1 (cols 0-8) because Z spawns cols 3-6. But no game over overlay. And no piece visible.

Wait, maybe it DID game over but showOverlay... overlay display flex should show. But screenshot shows no overlay. Hmm. Let me look: there's no falling piece visible. Maybe the piece spawned and is at y=-1 with cells above visible only... Actually for J spawn shape [[0,0],[0,1],[1,1],[2,1]] at x=3: cells (3,0),(3,1),(4,1),(5,1). Board rows 0,1 cols0-8 occupied → collides at spawn (y=-1? spawn y = -1!). SPAWN_Y=-1. So cells at y=-1+0=-1 (above board, not collided because y<0 skip) and y=0 for (0,1)->(3,0) collides with board[0][3]. So collides true. Then spawn tries piece.y -=1 → y=-2; cells y=-1 and y=-1? shape (0,1) → y=-1 <0 skip, so no collision. So it succeeds and piece is at y=-2, entirely above the board! So no game over, and no visible piece. Then gravity will move it down... and eventually it may collide. Actually at y=-2, moving to y=-1: cells (3,-1),(3,0)... (3,0) collides. So it can't move; it will lock in place at y=-2, writing only cells with y>=0, i.e., (3,0) etc. Then clearLines — rows still not full. Then spawn next... This means game over is delayed but eventually happens.

So the spawn rescue (nudging up) is causing a piece to spawn entirely above the board. That's a legitimate design for spawn, but it delays game over. In standard Tetris, if spawn position collides you try shifting up, and if still blocked it's game over. Here shifting up "succeeds" because cells go above board, so no game over but piece is invisible until it locks. That's a real usability bug: a piece can spawn fully off-screen and the player sees nothing.

Actually wait, in my code spawn: `if (collides(piece)) { piece.y -= 1; if (collides(piece)) { piece.y += 1; endGame(); ... } }`. So it only allows ONE nudge up. With y=-1 → y=-2. At y=-2 it doesn't collide. So piece is partly offscreen (all 4 cells at y=-1 or so). Not visible. Then gravity: test y+1 from y=-2 to y=-1: shape cells for Z? Actually the piece was Z. Let me recompute Z spawn shape [[0,0],[1,0],[1,1],[2,1]] at x=3,y=-2: cells (3,-2),(4,-2),(4,-1),(5,-1) — all y<0. Move down to y=-1: (3,-1),(4,-1),(4,0),(5,0). (4,0) and (5,0) occupied → collide. So it locks at y=-2, writing only... none? cells all y<0 except none >=0. So lock writes nothing! Then clearLines, spawn next. This could loop: pieces spawn above board, immediately get stuck at y=-2, lock with no cells written, forever. Board stays, no game over. That's a bug — game over never triggers in this situation.

Actually spawn next piece: piece = nextPiece at y=-1; collides → nudge to y=-2; not collide → spawn succeeds. It never triggers game over because the nudge always escapes upward. So game over only triggers if at y=-2 still collides, which requires two occupied rows above? For board with rows 0,1 full, y=-2 piece cells are at y=-2,-1, none in board, so never collides. So Game Over effectively never happens when top rows full!

This is a genuine bug. I need to fix spawn logic. Standard approach: if spawn position collides, it's game over (don't nudge). Or allow the piece to be partially above the board but game over when it can't be placed. The proper tetris: pieces spawn at rows 0-1 (some at row 20 hidden). If occupied, game over.

Simplest robust fix: at spawn, if collides at y=-1, try nudging up by 1 only if needed and game over if still collides. But the issue is the nudge makes it non-colliding above board. Instead, I should treat any cell above the board as acceptable for spawn only if the piece's visible portion fits. Actually the real fix for game over: check if spawn collides; if it does, game over. Don't nudge. 

But why did I add nudge? For I piece spawn where y=-1 and row 0 might be occupied... Actually standard spawn uses y=-1 and the I shape has cells at rot0 y=1 offset, so I cells at y=0. All pieces have their cells at y>=0 except some at y=-1? Let me check: each shape's smallest y is 0. With piece.y=-1, cells are at y=-1..? No: shape coords are 0-based. So cells = y + shape y. With y=-1, cell rows are -1, 0, 1. For most pieces, half the cells at row -1 (hidden) and half at row 0. That's the standard "spawn partially hidden". So at spawn, the visible row 0 must be free, otherwise game over. Nudging up lets it hide more, which is wrong per this implementation.

Better: spawn at y=0 so all cells visible? Then require rows 0-1 free. But standard spawn at -1 is fine. The condition: if collides(piece) at spawn → game over immediately. Because spawn cells at y=-1 are ignored and row0/1 must be free. If occupied → game over. No nudge.

But wait, some pieces like I at y=-1: cells (3,0),(4,0),(5,0),(6,0) all at row 0. Fine. So spawn collision → game over is correct.

Let me remove the nudge logic entirely: 
```
function spawn() {
  piece = nextPiece || makePiece(nextType());
  nextPiece = makePiece(nextType());
  if (collides(piece)) { endGame(); drawNext(); return false; }
  drawNext();
  return true;
}
```

This fixes game over. Let me apply.

Then re-test game over with cheat.

Also the score NaN won't occur in real play.

Let me fix.

Also, in spawn, `piece = nextPiece || makePiece(nextType())` — at reset, nextPiece is set, so piece = nextPiece. Then nextPiece = new. Good. But when spawn called from lock with piece=null, nextPiece is always set. Good.

Now there's a subtle issue: when game over happens, `draw()` is called after in lock() regardless: `if (!gameOver) spawn(); draw();` So draw shows the final board. Good.

Also updateHUD not needed.

Let me reload and test game over again with cheat "0". But wait, the cheat fills rows 0 and 1 minus col9, then hardDrop current piece. Current piece at spawn overlaps rows 0/1? The piece currently is at y=-1 (top). When I fill board rows 0,1, the piece's visible cells at row0 now overlap. hardDrop tests y+1 and collides, locks in place at y=-1, writing only row0 cells? Actually some cells at y=-1 (ignored) and row0. Rows 0,1 full minus col9? The piece might not fill col9. So no clear. Then spawn next → collides → game over. Good.

Let me reload and test.

Game Over now works. Restart from game over should reset. Let me press R. It should reset. Also verify the game over card text uses innerHTML with · which rendered as "·". Good.

Now remove the temporary cheat key handlers. Let me edit out the 9/8/0 handlers.

Restart from Game Over works: empty board, new L piece at top, next O, score 0, lines 0, level 1.

Now remove the cheat key handlers. Let me edit the file to remove the three cheat lines.

Now final reload and a quick sanity screenshot, plus check console errors. Also verify no cheat keys. Let me reload and inspect, plus do one move/rotate/hard-drop smoke test.

Clean, no console errors. Final smoke test: rotate the I piece and hard drop. Let me do it to ensure the fix didn't break spawn.

I piece rotated to vertical and hard-dropped to the bottom. A new T piece spawned at top, and next preview advanced from T to S. Everything works.

Final file is clean. Let me quickly confirm the file has no leftover cheat keys by grep.

All good. Final report.

I did the required verification:
- Move/rotate/hard-drop: worked, piece locks, new spawns, next preview advances.
- Pause/resume: overlay, resume.
- Restart: resets board/score/level.
- Line clear scoring 1-line (100), 4-line (800), level up at 10 lines (tested via temporary hooks, now removed).
- Game over: found and fixed a spawn bug; verified game over overlay and restart.
- Console: no errors.

Unverified: 2-line (300) and 3-line (500) specifically, T-spin, wall kicks (not supported, by design), high-speed levels beyond 2, real-time gameplay scoring through actual play.

Let me write brief report.