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Pentomino Puzzle is the classic tiling puzzle, free in your browser. There are exactly twelve ways to join five squares edge to edge, named after the letters they look like — F, I, L, N, P, T, U, V, W, X, Y and Z — and the challenge is to pack them into a box so every square is covered exactly once. Drag a piece from the tray onto the board, turn it with a right-click or the turn button, flip it over, and drag it off again if it is wrong. The first five levels deal you three to eight pieces for a small box, drawn from a seed and each set proved to fit before you see it. Then come all twelve: the famous 6×10 box, 5×12, a staircase, Dana Scott’s 8×8 with a hole in the middle, a plus sign, and finally the 3×20 strip, which can only be packed two ways. A red square warns you when you have walled off a gap no piece can fill, and a hint places one piece of a real packing. No download, no account.
How to play Pentomino Puzzle
- Each level is a box and a tray of pieces. Every piece is a pentomino: five squares joined edge to edge.
- Drag a piece from the tray onto the board. It snaps to the squares, shows green where it fits and red where it does not.
- Turn the piece in your hand with a right-click, the Turn button or R. Flip it over with the Flip button or F. On a phone, tap a second finger while dragging to turn it.
- You can also tap a piece in the tray to pick it up, then tap the board to put it down there.
- Drag a piece already on the board to move it, or drop it off the board to send it back to the tray. Tapping it lifts it back into your hand.
- The box is packed when every piece is on the board and every square is covered exactly once.
- A square outlined in red is part of a gap that can never be filled — its size is not a multiple of five — so something nearby has to move.
- On a keyboard, Q and E choose a piece, the arrow keys move it, R turns and F flips it, and Enter puts it down or picks one up. Backspace lifts the piece under the cursor.
- The ? button places one piece of a real packing, lifting any pieces that cannot be part of one. Three per box: no hints is three stars, one hint is two.
- Undo steps back one move and Clear empties the box. On the first five levels, New Pieces deals a different set.
Tips
- Start in a corner and along the edges. A piece in the middle of the box leaves awkward gaps on every side.
- Place the awkward pieces early. The X fits in very few places — it can never touch an edge with its centre — and the long I is easiest along a wall.
- Count the gaps. Any closed-off region has to be a multiple of five squares; a pocket of three or seven means a piece has to move.
- Save the flexible pieces — L, N, P and Y, which come in eight orientations each — for the end, when you need something to fill a leftover shape.
- On the long boxes, fill from one short end towards the other rather than scattering pieces along the length.
- Stuck on a big box? A hint that lifts pieces is telling you those were wrong. It offers every piece back one at a time and keeps each one a packing still allows, so a wrong early piece does not take the right ones placed after it off too.
- The 3×20 strip has only two packings, not counting turns and mirror images of the whole strip. If you get it without a hint, you have found one of them.
FAQ
Is Pentomino Puzzle free to play?
Yes. It runs in the browser with no download, no sign-up and nothing to buy. All thirteen levels are included and unlock as you pack each box.
What is a pentomino?
A shape made of five squares joined edge to edge. Counting turns and mirror images as the same shape, there are exactly twelve of them, usually named after letters they resemble: F, I, L, N, P, T, U, V, W, X, Y and Z. Solomon Golomb named them in 1953, and they have been a favourite puzzle ever since.
How many ways can the 6×10 box be packed?
2,339, not counting turns and mirror images of the whole box as different. The game's solver counts them in the tests, along with the other famous totals: 1,010 for 5×12, 368 for 4×15, 2 for 3×20, and 65 for the 8×8 with a 2×2 hole in the middle.
Can every level be solved?
Yes, and it is checked rather than assumed. Every box has been packed by an exact-cover solver, and on the first five levels, where the pieces are dealt from a seed, a set is only handed out once the solver has packed it.
Can I flip the pieces over?
Yes. Pentomino puzzles treat mirror images as the same piece, so every piece can be turned a quarter at a time and flipped over, whichever way the box needs it.
Which level is the hardest?
The last one. From level 6 on, every box takes all twelve pieces, and they are ordered by how many ways they can be packed, counting turns and mirror images separately. The first four have thousands; then come 1,472 for 4×15, 520 for the holed 8×8, 18 for the plus sign and 8 for the 3×20 strip. Fewer packings means fewer answers to stumble on.
What do the red squares mean?
They mark a closed-off gap whose size is not a multiple of five. Every piece covers five squares, so a gap of, say, three or seven can never be filled, and one of the pieces around it has to move. A gap of five or ten is not marked, even if no piece happens to fit it.
Does it work on a phone?
Yes. Drag pieces with a finger and tap a second finger while dragging to turn one, or tap a piece and then tap the board. The game rearranges itself to fit the screen, and on an upright phone it stands long boxes like 3×20 on end so the squares stay large.