In a plane, an arrangement of *n* congruent squares joined to one another by at least one of their sides.

- A polyomino formed by 2 squares is called a
**domino**. - The 2 polyominoes formed by 3 squares are called
**trominoes**. - The 5 polyominoes formed by 4 squares are called
**tetrominoes**. - The 12 polyominoes formed by 5 squares are called
**pentominoes**. - The 35 polyominoes formed by 6 squares are called
**hexominoes**.

### Examples

- These are the 12 pentominoes:

The eight pentominoes in blue illustrate the possible nets of a box without a lid.

- The 35 hexominoes:

The eleven hexominoes in red illustrate the possible nets of a cube.

### Historical note

The term “polyomino” was first used in 1952 by Solomon W. Golomb, a professor at the University of Southern California in the United States. This concept inspired the development of popular games like Tetris and Pentamino.