The Gomboc is a roundish piece of clear synthetic material with gently peaked, organic curves. It looks like a piece of modern art. But if you tip it over, something unusual happens: it rights itself.

It leans off to one side, rocks to and fro as if gathering strength and then, presto, tips itself back into a “standing” position as if by magic. It doesn’t have a hidden counterweight inside that helps it perform this trick, like an inflatable punching-bag doll that uses ballast to bob upright after you whack it. No, the Gomboc is something new: the world’s first self-righting object.

Image The Gomboc is the physical realization of a mathematical theorem: that a "mono-monostatic" object -- one that has a single stable point of equilibrium, or balance -- must exist. And so it does. No matter how you orient it, the Gomboc always rights itself. Credit... Illustration by Bryan Christie Design

The Gomboc is a result of a long mathematical quest. In 1995, the Russian mathematician Vladimir Arnold mused that it would be possible to create a “mono-monostatic” object — a three-dimensional thingy that purely by dint of its geometry had only one possible way to balance upright.