What Leonardo da Vinci invention was a four-wheeled cart that could move without being pushed?

Leonardo da Vinci's self-propelled cart was a four-wheeled vehicle designed to move without being pushed by a person or animal.

Leonardo drew the cart in the early sixteenth century, probably around 1478–1480. Its motion came from coiled springs housed inside the vehicle. The springs could be wound before release, while a system of gears transferred their stored energy to the wheels.

The cart also included steering and a mechanism that could control how far it traveled. Because the design was intended to perform in a courtly setting, historians often describe it as an early programmable automaton or stage vehicle rather than a practical automobile.

The cart is sometimes called the world's first self-propelled vehicle, but that label depends on how “vehicle” is defined and on the interpretation of Leonardo's drawing. Modern reconstructions have shown that the mechanism can work, though they necessarily fill in details that Leonardo left incomplete. It had no engine in the modern combustion or electric sense.