Rolling Tetrahedron

Reuleaux Tetrahedron (50 mm)

 

The Reuleaux tetrahedron is a fascinating geometric shape that rolls in a surprisingly smooth and consistent way when placed between two flat surfaces. Although its edges are not perfectly constant width, they come close enough to fool your intuition — which is exactly what makes it so fun to play with.

This shape is formed from the intersection of four spheres, giving it a unique rolling motion that feels unusual yet steady. Watching it move is oddly satisfying and a great conversation starter for anyone interested in geometry, engineering, or mechanical motion.

 

Assembly:

Push the triangular connector into place between the two halves. The fit is intentionally tight, so some force may be required. This tight fit keeps the parts properly aligned and is essential for achieving the smooth rolling behavior.

Boost MeModels like this are not easy to make!😅 The best way to support me is be pressing this button! Your support helps me keep the models coming. :)