What was Leonardo da Vinci's wheeled device designed to move without being pushed by people or animals?

Leonardo da Vinci's self-propelled cart was designed to move without being pushed by people or animals.

The cart appears in a drawing from the Codex Atlanticus and is often described as an early ancestor of the automobile. Its motion came from coiled springs mounted inside the chassis. A system of gears controlled the release of stored energy, while a steering mechanism could set the direction.

The machine may have been intended for theatrical performances or court spectacles rather than transport. Leonardo worked for patrons who staged elaborate events, and a vehicle that moved by itself would have created a dramatic effect. The design was not a motor car because it had no internal-combustion engine.

In 2006, researchers built a working replica at the Museo Galileo in Florence. The replica demonstrated that the basic mechanism could operate, although modern reconstructions necessarily interpret parts of Leonardo's incomplete design.