A plane figure has rotational symmetry about a point O if rotation about O through some angle 0^∘<θ‎<360^∘ is a symmetry of the figure. For example, an equilateral triangle has rotational symmetry about its centre. The order of rotational symmetry about O is the number of such rotations in the range 0^∘≤θ‎<360^∘; so, the equilateral triangle has order 3.