The double cone seems to defy the gravitational force of the Earth and roll uphill. In reality, the cone is sinking lower as the track widens, so its centre of gravity is actually moving downward.

When a symmetrical double cone is placed on the narrow end of a triangular track, the centre of its mass pulls it downward, causing the cone to roll forward along the upward and widening track. When an object is supported at its centre of gravity, it is in balance in relation to external forces.

The question regarding a moving centre of gravity is based on Newton’s double cone paradox.