What vehicle did Leonardo da Vinci sketch as a self-propelled cart powered by coiled springs?

Leonardo da Vinci sketched a self-propelled cart powered by coiled springs.

The cart appears in drawings from around 1478 to 1480. Its mechanism used two symmetrical springs wound inside drum-like units. As the springs unwound, gears transferred their motion to the wheels. Steering could be set in advance, allowing the vehicle to follow a predetermined path rather than being driven by a person sitting inside it.

The design has often been called an early ancestor of the automobile, but that comparison needs care. It had no engine, no modern steering system, and no means of continuously supplying power. It was closer to a large mechanical toy or stage device than to a road car.

A working reconstruction was built in the modern period from Leonardo’s drawings. The cart is also associated with theatrical machinery and has sometimes been linked to possible Renaissance court spectacles, although the original intended use is not completely certain.