About polyomino

What is a polyomino?

A polyomino is a shape made by joining unit squares edge-to-edge. The smallest non-trivial one is the domino (two squares), followed by the tromino (three), the tetromino (four), and the pentomino (five). The name was coined by the American mathematician Solomon W. Golomb in 1953 and popularised in his book Polyominoes: Puzzles, Patterns, Problems, and Packings. They have been a fixture of recreational mathematics and puzzle design ever since — most famously, the seven distinct tetrominoes are the falling pieces in Tetris, which Alexey Pajitnov released in 1984.

In polyomino.io your figure literally is one of these shapes: as you eat food you grow square by square, and the arrangement of those squares becomes your piece. Where Tetris hands you a fixed bag of pre-built shapes, polyomino.io lets each player build their own through the order they collect food in. No two pieces feel exactly the same.

Why several modes?

Each mode in polyomino.io takes the same primitive — drift around a 2D arena, collect, dock — and asks a different question about what to do with it.

• FFA asks "can you take ground and hold it?" It's a real-time land grab built on the Tetris-style piece kit: you seed a small block of your own colour, then grow it by docking finished tetrominoes, shoot holes in rivals' walls one tile at a time, and connect against a neighbour to fence them in and wipe them off the board. Blanket the most of the arena to take the round.
• Pentomino asks "can you cooperate without coordinating?" The picture in the centre of the world fills slowly, with strangers' pieces locking in alongside yours. There's no chat, no team — just a shared image that everyone is incrementally completing. The mode rewards careful, deliberate drops over fast ones.
• Domino asks "can you read the board?" Rounds are short and the win condition is simple — a chain from one wall to the other — but the colour-match docking rule means you constantly have to weigh whether to start your own bridge or to extend someone else's.

Design philosophy

Real-time, not turn-based

Most polyomino puzzles you'll find online are static: arrange a fixed set of pieces inside a fixed outline. polyomino.io throws that out and runs the whole thing as a real-time multiplayer arena. Pieces move, collide, and die. The mathematical elegance is still there — pentominoes really do tile their pictures exactly — but you have to navigate the chaos of other players while you solve the puzzle.

One playfield, three rulesets

Every mode runs on the same engine and the same set of verbs. There's a single canvas, a single set of inputs, and a single visual language of coloured squares. That shared vocabulary means you can pick up any mode in under a minute, even if you've never played the other two.

No accounts, no ranked play

polyomino.io is intentionally drop-in. There are no accounts, no levels, no progression bar — just a nickname and a round. We think a game should be fun on the first session, not on the fiftieth.

Contact

Bug reports, feature ideas, and just-saying-hi emails are all welcome at [email protected]. For legal contact information see the Impressum.