Heptagon

A heptagon is a plane figure with seven sides and seven angles. In a regular heptagon, in which all sides and all angles are equal, the sides meet at an angle of approximately 129.6 degrees.

The United Kingdom currently (2003) has two heptagonal coins, the 50p and 20p pieces. Strictly, the shape of the coins is a curvilinear heptagon: the sides are curved outwards so that the coin will roll smoothly in vending machines.