What type of machine did Leonardo da Vinci design with two spring-powered wheels and a steering caster?

Leonardo da Vinci designed a self-propelled cart with two spring-powered wheels and a steering caster.

The cart was drawn around 1478–1480 and is often described as an early programmable machine. Its motion came from coiled springs hidden inside the main wheels. A system of gears transferred the spring energy to the wheels, while programmable blocks or cams could determine the route and cause the cart to turn.

The design may have been intended for theatrical performances or court celebrations rather than transport. Leonardo’s notes do not clearly state its exact purpose, so claims that it was a practical automobile are too strong. It also had no engine and could travel only for a limited distance before its springs unwound.

A modern reconstruction was built and demonstrated in the early 21st century. The cart is often connected with Leonardo’s later mechanical lion and robot studies, but those were separate designs. Its importance lies in the early use of stored mechanical energy and programmable movement in a mobile device.