What mechanical device did Leonardo da Vinci design to move without an animal pulling it?

Leonardo da Vinci designed a self-propelled cart to move without an animal pulling it.

The device, sketched around 1478 to 1480, used coiled springs to store energy. When released, the springs turned the cart's wheels through a system of gears. A steering mechanism could be set in advance, allowing the vehicle to follow a predetermined path rather than being guided continuously by a driver.

Because it could move under its own stored power, the cart is often described as an early ancestor of the automobile or robot. Those comparisons are useful but limited. It had no combustion engine, no rechargeable battery, and no modern feedback or navigation system. Its operation depended on mechanical energy wound into springs before use.

The cart may have been intended for theatrical performances or court spectacles, where a moving object could create an impressive stage effect. A working reconstruction displayed at the 2006 Florence exhibition showed that the basic mechanism could function. The design demonstrates Leonardo's interest in automation, controlled motion, and hidden mechanical power.