What type of machine did Leonardo da Vinci design to move itself using gears and a wound spring?

Leonardo da Vinci designed a self-propelled cart using gears and a wound spring.

The machine appears in drawings from around 1478 to 1480 and is often described as an early ancestor of the automobile. Two large rear wheels support the cart, while a complicated gearing system transfers energy from coiled springs to the wheels. Steering could be set in advance, allowing the cart to follow a predetermined path.

The cart was probably intended for theatrical or ceremonial use rather than ordinary transport. A reconstruction built for an exhibition in 2006 showed that the basic mechanism could work, although the original design has been interpreted in different ways.

Leonardo did not have an internal-combustion engine. Its stored mechanical energy came from springs, making the machine closer to a wind-up vehicle than to a modern car. The design is significant because it combined propulsion, gearing, and programmable steering in one compact mechanism.