Polyomino
![The 35 free hexominoes, colored according to their symmetry.](/Images/godic/202502/03/All_35_free_hexominoes.svg1800.png")
![The 108 free heptominoes.](/Images/godic/202502/03/Heptominoes.svg1800.png")
![The single free domino.](/Images/godic/202502/03/Domino_green.svg1800.png")
![The two tiling nonominoes not satisfying the Conway criterion.](/Images/godic/202502/03/Conway_criterion_false_negative_nonominoes.svg1801.png")
A polyomino is a plane geometric figure formed by joining one or more equal squares edge to edge. It is a polyform whose cells are squares. It may be regarded as a finite subset of the regular square tiling with a connected interior.
Polyominoes are classified according to how many cells they have: