What clockwork device did Leonardo da Vinci design to move without being pushed or pulled by a person?

Leonardo da Vinci designed a self-propelled cart that could move without being pushed or pulled by a person.

The cart, drawn in Leonardo’s notebooks around 1478–1480, used coiled springs as its source of energy. As the springs unwound, a system of gears transferred motion to the wheels. Steering could be set in advance, allowing the cart to follow a predetermined path.

Because it could move automatically, the device is often called an early robot or the ancestor of the modern automobile. It was not an automobile in the modern sense: it had no engine, passenger body, brakes, or independent steering system.

The cart’s original purpose is uncertain. Some historians have suggested that it might have been designed as a theatrical prop for court festivities, where a moving object could surprise spectators. A replica built in the twentieth century demonstrated that the mechanism could work when reconstructed from Leonardo’s drawings.