Block Fit

How to play

Drag a piece from the tray onto the board, with a mouse or a finger. The board shows where it would land before you let go. On a phone the piece is drawn a little above your finger, so it is not hidden by it.

Fill a whole row or a whole column and it clears. Both count, and every completed line goes at the same moment.

All three pieces have to go down before the next three arrive, and the run ends when none of the pieces you are still holding fits anywhere.

Rules and controls

• Three pieces are offered at a time.
• A piece goes anywhere it fits entirely on empty squares.
• Once a piece is down it stays down — there is no undo.
• Rows and columns both clear, and all completed lines go together.
• All three must be placed before the next three are dealt.
• The run ends when nothing you are holding fits.
• With a keyboard: Tab to a piece, Enter to pick it up, the arrow keys to move it, Enter to place it, Esc to put it back.

Modes

• Classic — Endless. Pieces go down as they come — no turning them.
• Relaxed — The same board, but you may turn a piece before placing it.
• 3 minutes — Classic rules against a three-minute clock. Runs do not resume.
• Daily — One piece stream a day, the same for everybody, from the UTC date.

Tips

• Keep a clear three-by-three somewhere. The square is the piece that ends runs, and it needs nine free squares in one block.
• Work from the edges inwards. A piece against a wall wastes nothing; a piece in the middle cuts the board into two smaller boards.
• Look at all three before placing any of them. The order is usually the whole decision — the piece that is awkward now may be the only thing that fits after the other two are down.
• A near-full row is worth finishing before it is worth extending. Lines that go together pay much more than lines that go one after another.
• Do not chase the combo into a corner. A streak is worth at most three times, and a board you cannot play is worth nothing.

Privacy and local play

Everything runs in your browser. Your current run, your settings and your best score for each preset are kept on this device only, and the button under the board clears them without touching any other Zerdly tool. No account, no sign-in, and nothing about your play leaves the machine you are on.

Questions

Do columns clear as well as rows?

Yes, and both at once. Every completed line goes at the same moment, so a piece that finishes a row and a column clears both — and it is worth more than clearing them one after the other, because doing it in a single placement is much harder to arrange.

Why can I not place a piece until I have used the other two?

Because the three arrive as a set and all three have to go down before the next set does. That is what makes the third piece the interesting one: you are not choosing where to put a piece, you are choosing an order for three of them.

Why is there no undo?

Because a placed piece staying put is the rule the whole game rests on. With undo you could try every square and keep whichever worked out, and the score would stop measuring anything — it is not that the game would be easier, it is that it would not be a score. New run starts again whenever you like.

Does the game give me easier pieces when I am nearly stuck?

No, and it cannot. The pieces are decided by the seed and the deal number alone — nothing in the generator can see the board, how full it is or how close you are to losing. That is checked by dealing the same seed to a game played to a standstill and to a game never played at all, and confirming the two streams match piece for piece.

So can I be dealt three pieces that do not fit?

Yes, and that is the game ending rather than the game cheating. What cannot happen is an opening set that will not go down: every one of the 5,456 possible three-piece deals has been checked against an empty board. After that, keeping room is your job.

How is Relaxed different from Classic?

You may turn a piece before placing it. That is a different game rather than an easier setting — most dead ends stop being dead ends — so its best score is kept separately. The board, the pieces and the scoring are otherwise identical.

What happens if I close the page mid-run?

Classic, Relaxed and the Daily are saved as you play and come back exactly as you left them. The three-minute run does not: a clock that kept running while the page was shut would lose you the game for closing a laptop, and one that stopped would turn three minutes into three minutes spread over an afternoon. Reloading starts a fresh timed run.

How does the daily puzzle work?

One piece stream a day, the same for everybody, built from the UTC date rather than your local one. The stream is regenerated from the date rather than stored, which is why the generator version is part of the key — a change that moved the pieces gets new keys instead of quietly reinterpreting old results. Your results stay on this device.

How does the combo work?

Clearing on consecutive placements builds it, and placing without clearing ends it. It multiplies what a clear is worth, up to three times. It is a ceiling for exceptional play rather than a number the ordinary game reaches — measured over forty games, the best streak was five.

Is anything sent to a server?

No. The pieces, the scoring, the sounds and your best scores all run in your browser. There is no account, and clearing this game's data leaves every other Zerdly tool untouched.

Related interactives

• Box Push — the other route where a move cannot be taken back.
• Traffic Escape — sliding pieces on a crowded grid, with a way out to find.
• Bridges — join numbered islands into one connected network.
• Slitherlink — draw a single loop that satisfies every clue.