What wheeled device did Leonardo da Vinci design to move without a horse or external animal power?

Leonardo da Vinci designed a self-propelled cart powered by wound springs rather than a horse or other animal.

The cart appears in drawings from around 1478 to 1480. Its mechanism used springs, gears, and a system for controlling the distance and direction of travel. The device may have been intended for theatrical performances or court spectacles, where it could move across a stage without an obvious driver.

It is often described as an early ancestor of the automobile, but that comparison needs care. Leonardo’s cart did not have an engine, steering wheel, or modern road system. In 2006, engineers and historians constructed a working model based on the drawings. The reconstruction demonstrated that the mechanism could move, although the surviving sketches leave some details open to interpretation.