What Leonardo da Vinci device was a spring-powered cart that moved without being pushed?

Leonardo da Vinci designed a spring-powered self-propelled cart that could move without being pushed.

The cart used coiled springs inside its body as a stored-energy source. When released, the springs turned drums and drove the wheels through a system of gears. Steering could be set in advance, allowing the vehicle to follow a predetermined path rather than being continuously guided by a driver.

Leonardo probably conceived the cart for theatrical or ceremonial use. A reconstruction was displayed at a 2006 exhibition in Florence, where researchers demonstrated that the mechanism could operate when built from the surviving drawings. The vehicle is therefore often described as an early ancestor of the automobile, although it was not powered by an engine.

It should not be confused with Leonardo’s armored vehicle design. The self-propelled cart was compact and intended for movement or spectacle; the armored vehicle was a separate military concept.