Revolved Reuleaux Triangle

A solid of constant width is a surface for which the thicnkess measured in any direction is the same. This means that, placed between two planes, the object can roll freely. Spheres are a prime example of this geometric phenomenon but are far from the only solids with the right properties.

These revolved Reuleaux triangles are another example of solids of constant width. If you place them on a table with a book or other flat object on top, you can roll the object smoothly. However, unlike spherical bearings, they won't roll away from you. Great for fiddling and fidgeting or simply exploring a unique property of geometry.