What Leonardo da Vinci invention could move itself using a spring-powered mechanism?

Leonardo da Vinci’s self-propelled cart was an early vehicle designed to move without being pushed by a person or animal.

Leonardo sketched the cart around 1478–1480. Two symmetrical springs stored energy and released it through a system of gears, while steering could be set in advance using a programmable mechanism. The vehicle was probably intended for theatrical displays or court festivities rather than for transporting people over long distances.

The cart is sometimes described as a robot because it could perform a programmed movement, but it was not an autonomous robot in the modern electronic sense. It had no computer, sensors, or feedback system. Reconstructions, including a working model displayed at the 2006 Florence Science Museum, have shown that the basic mechanical concept could function when built according to the surviving drawings.