Roly-poly toy

A roly-poly toy, round-bottomed doll, tilting doll, tumbler or wobbly man is a toy that rights itself when pushed over. The bottom of a roly-poly toy is round, roughly a hemisphere. Many roly-poly toys are hollow, with a weight inside the bottom. They have a center of mass below the center of the hemisphere, so that any tilting raises the center of mass. When such a toy is pushed over, it wobbles for a few moments while it seeks the upright orientation, which has an equilibrium at the minimum gravitational potential energy.