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 , 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 , the cyclic group of order 2.