What machine did Leonardo da Vinci design to help a person move a cart without animals?

Leonardo da Vinci designed a self-propelled cart to move without animals or a person pushing it.

The drawing appears in Leonardo's Codex Atlanticus and shows a wheeled vehicle powered by coiled springs. As the springs unwound, they transmitted motion through gears to the wheels. A steering mechanism and programmable control features were also included in the design, making the cart more than a simple spring-powered toy.

The cart was probably intended for theatrical performances or court entertainments rather than transportation. Leonardo's mechanism could be adjusted so that the vehicle followed a predetermined path. It therefore resembles an early programmable machine as well as an early automobile concept.

The cart was not a practical road vehicle in the modern sense. It had limited stored energy and no engine comparable to a later internal-combustion motor. Reconstructions built from Leonardo's drawings have demonstrated that the mechanism can work, although historians debate details of the original design and its intended use.