This 3D Meissner body is a revolution of 2D Reuleaux triangle.[br][br]There exists a different shape, the Reuleaux tetrahedron, that is the intersection of four spheres centered at the vertices of a regular tetrahedron. However, that shape is not a 3D shape of constant width.[br][br]Also check out [url=https://www.geogebra.org/m/cdwgu2q9]shapes of constant width 2D (Reuleaux polygons)[/url].