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.
- 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.
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.