What did Leonardo da Vinci design as an early spring-powered vehicle around 1478–1480?

Leonardo da Vinci designed a self-propelled cart around 1478–1480.

The compact three-wheeled machine was intended to move without being pushed by a person or pulled by an animal. Two symmetrical springs supplied stored energy, while a programmed steering mechanism helped determine the cart’s path.

The design is often described as an early robot or automobile precursor, but those descriptions need qualification. It carried no engine and was not a practical road vehicle. Its purpose may have been theatrical, such as creating an automatic stage effect at a court celebration.

The cart was reconstructed in modern times from Leonardo’s drawings. Reconstructions helped demonstrate that the mechanism could move, although details of the original design remain uncertain because Leonardo’s notes are incomplete.