Meissner Solids

A yellow and black exhibit table and information panel. On the table top sits blue and green solid shapes and a square glass plate.
A yellow and black exhibit table and information panel. On the table top sits blue and green solid shapes and a square glass plate.

Different shapes (including spheres) roll smoothly across a surface.

How it works

Roll a square plate on top of different-shaped solids, and feel which shapes allow the plate to roll smoothly.

Things to try or ask around the exhibit

Can you find other shapes that will allow the plate to roll just as smoothly?

Background

Although some shapes appear to be irregular, the plate rolls smoothly due to the shapes’ constant widths. This exhibit uses different shapes such as spheres, a Reuleaux tetrahedron, a Reuleaux triangle and a Meissner body. One of these shapes looks like an acorn, but it actually has a constant width, so it rolls in a similar manner as a sphere.