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Nonomino


A nonomino (or 9-omino) is a polyomino of order 9, that is, a polygon in the plane made of 9 equal-sized squares connected edge-to-edge. The name of this type of figure is formed with the prefix . When rotations and reflections are not considered to be distinct shapes, there are 1,285 different free nonominoes. When reflections are considered distinct, there are 2,500 one-sided nonominoes. When rotations are also considered distinct, there are 9,910 fixed nonominoes.

The 1,285 free nonominoes can be classified according to their symmetry groups:

Reflection-symmetric-nonominoes-90-deg.svg

Reflection-symmetric nonominoes 45-deg.svg

C2-Rotation-symmetric nonominoes.svg


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