What kind of cart did Leonardo da Vinci sketch that could move without being pushed by animals?

Leonardo da Vinci sketched a self-propelled cart powered by wound springs.

The cart, drawn around 1478–1480, used two large coiled springs beneath its body. The springs stored mechanical energy, while a system of gears transferred that energy to the wheels. A steering mechanism could also be set in advance, allowing the cart to follow a predetermined route.

Because it could move without a horse or a person pushing it, the machine is often described as an early robot or the ancestor of the automobile. It was not powered by an engine and could not be steered continuously like a modern car. Its likely uses included stage effects, ceremonies, or theatrical demonstrations.

The original device has not survived. In 2006, engineers and historians built working replicas from Leonardo’s drawings, confirming that the mechanism could function when interpreted carefully.