Some trapeziums have one line of symmetry. They are called isosceles trapeziums as they have 2 sides of an equal length like isosceles triangles. A trapezium has rotational symmetry of order one.

Some trapeziums have one line of symmetry. They are called isosceles trapeziums as they have 2 sides of an equal length like isosceles triangles. A trapezium has rotational symmetry of order one.

Surprisingly, when the quadrilateral is a parallelogram ... in a cyclic configuration leads to different types of rotational symmetry that can be achieved as the structure folds in on itself.