# Rotational symmetry (2-fold)

A polyomino has *2-fold rotational symmetry* if it is identical to its 180˚ rotation. This type of symmetry is represented by $C_2$, the cyclic group of order 2.

A polyomino has *2-fold rotational symmetry* if it is identical to its 180˚ rotation. This type of symmetry is represented by $C_2$, the cyclic group of order 2.