What Leonardo da Vinci machine used gears and wheels to move without a person pushing it?

Leonardo da Vinci designed a self-propelled cart that could move without a person pushing it.

The cart appears in drawings from the late 15th century and is powered by coiled springs housed in drums. Gears transfer the spring force to the wheels, while a programmable steering system uses pegs to determine the cart's path. This makes it an early mechanical vehicle concept rather than a motor car.

The design is sometimes described as an ancestor of the automobile, but it had no engine and could travel only for a limited distance. Its exact purpose is uncertain. Historians have suggested that it may have been intended for theatrical performances or court entertainments, where an object could move across a stage automatically.

A full-scale reconstruction by the Institute and Museum of the History of Science in Florence was demonstrated in 2006. The reconstruction showed that the mechanism could work, although details of the original design remain open to interpretation.