Reuleaux polygon

As a special case, this construction is possible for every regular polygon with an odd number of sides.

However, it is possible for other curves of constant width to be made of an even number of arcs with varying radii.

For instance, the United Kingdom has made 20-pence and 50-pence coins in the shape of a regular Reuleaux heptagon.

[5] The Canadian loonie dollar coin uses another regular Reuleaux polygon with 11 sides.

[7] Although Chinese inventor Guan Baihua has made a bicycle with Reuleaux polygon wheels, the invention has not caught on.

A Reuleaux triangle replaces the sides of an equilateral triangle by circular arcs
Gambian dalasi coin, a Reuleaux heptagon
Four 15-sided Reinhardt polygons, formed from four different Reuleaux polygons with 9, 3, 5, and 15 sides