Shape Shift

Sixteen tiles, each showing a circle, a triangle, a square or a diamond. Tap one and it advances a step along that cycle — and so do the tiles above, below, left and right of it. Get every tile onto the same shape before the taps run out. The catch is that four taps on one tile bring it all the way back to where it started, so the question is never "which tiles do I flip" but "how many times does each tile need pressing".

It runs entirely on your device: 0 network requests, works offline. No ads, no account, nothing to buy, and no betting, money or prizes of any kind.

1. Focus the board — click it, or press Tab until it is focused.
2. Move the cursor with the arrow keys. It stops at the edges rather than wrapping.
3. Tap a tile with Enter, or click it. The tile and its four orthogonal neighbours each move one shape forward: circle to triangle to square to diamond and back to circle.
4. Read the ×n in each tile's corner. That is how far through its four-step cycle your taps have taken it — a tile showing ×0 is contributing nothing, however often you tapped it.
5. Match every tile before the tap counter reaches its budget. Any of the four shapes counts as a win, so aim for whichever one the board is already closest to.

How do you solve a grid puzzle where tapping one tile changes its neighbours too?

Stop thinking in taps and start thinking in counts. Because the taps do not interfere with each other — tapping A then B leaves exactly the board that tapping B then A would — a solution is just a number from 0 to 3 for every tile, and the order you enter them in cannot change the outcome. That turns the puzzle into arithmetic you can do a row at a time. Choose what the top row's four counts will be, and then every row underneath is forced: the only tile left that can still change a tile in the row above it is the one directly below, so its count is whatever brings that tile onto your target shape. Work down to the bottom, and either the last row lands on the target or your opening guess was wrong and you try another. That is exactly the method this game's own solver uses to work out the move budget before you ever see the board.

Is every board actually solvable?

Yes, by construction. A board is made by starting from a finished one — every tile the same shape — and running the game backwards a handful of times, each step being the exact inverse of a legal tap. The forward sequence that undoes the scramble therefore always exists. Nothing is generated at random and hoped over, so no board here can be impossible, and none of them needs an undo button to rescue it.

Why can't I just tap the same tile again to undo a mistake?

Because the cycle has four steps, not two. In a two-state version of this puzzle a tap is its own undo, which is what lets people solve those by pressing things twice and watching what happens. Here a mistaken tap costs you three more taps of the same tile to come back round — which is exactly what the tap budget's margin is sized for: enough to absorb one wrong tile, and not two.

How is the tap budget decided?

By solving the board. Before the puzzle is handed to you, the game works out the true minimum number of taps that clears it, and the budget is that number plus a fixed margin of four. It is never a guess and never a round number picked for feel: a budget that could not be met would be unfair, and one much larger than the optimum would remove the reason to plan.

Do I need to see colour to play this?

No. The state of a tile is a shape — circle, triangle, square, diamond — and the fill behind it only repeats what the glyph already says. The screen reader announces each tile by shape name along with its tap count, and every square is reachable with the arrow keys alone.

Is there any money, betting or in-app purchase in this?

None, and there never will be. No currency, no prizes, nothing to buy, no wagering of any kind — the whole game is the sixteen tiles in front of you.

Does it work offline?

Yes. Once the page has loaded once, the entire game lives on your device: the board, the generator and the solver all run in your browser, and nothing is sent anywhere at any point.

A four-by-four board with a four-shape cycle. Boards are built from five to eight reverse taps, and the budget is the solver's own minimum plus four. There is no undo and no hint — the ×n counters are the hint, and they are always visible.

Light Grid is this puzzle's two-state ancestor: same plus-shaped tap, but a light is only on or off, so a tap undoes itself. Colour Sort is the other tile puzzle here, and it shares the same generator discipline — built backwards from a solved position, so nothing dealt to you is impossible.

Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.