What self-moving invention did Leonardo da Vinci design using a spring-powered mechanism?

Leonardo da Vinci designed a self-propelled cart using a spring-powered mechanism. The machine is often described as an early programmable vehicle or ancestor of the automobile.

Leonardo’s drawing shows a three-wheeled cart. Two large driving wheels were connected to coiled springs, while a smaller front wheel provided steering. The springs could be wound in advance, allowing the cart to move without a person pushing it continuously.

The design also included a system of pegs and stops that could control the distance and direction of travel. That feature made the machine useful for theatrical performances, where it may have been intended to move automatically as a stage effect.

The cart was not a modern automobile: it had no engine, fuel system, or passenger cabin. A full-scale reconstruction displayed in 2006 demonstrated that the mechanism could work when built from Leonardo’s surviving drawings. Its importance lies in combining stored mechanical energy, steering, and pre-set movement in one compact device.