Reuleaux may refer to: Franz Reuleaux (1829–1905), German mechanical engineer and lecturer in geometry: Reuleaux polygon, a curve of constant width Reuleaux triangle, a Reuleaux polygon with three sides Reuleaux heptagon, a Reuleaux polygon with seven sides that provides the shape of some currency coins Reuleaux tetrahedron, the intersection of four spheres of equal radius centered at the vertices of a regular tetrahedron