What Leonardo da Vinci design used a four-wheel platform with a wound spring to move without being pushed?

Leonardo da Vinci’s four-wheel, spring-powered vehicle design was the self-propelled cart.

Leonardo sketched the cart around 1478 to 1480. Its movement came from coiled springs, similar in principle to the springs used in Renaissance clocks. The springs were wound before operation, and gears transferred their stored energy to the wheels. Steering could be programmed through a system of shaped blocks, allowing the cart to follow a predetermined path.

The machine is sometimes called Leonardo’s car, but it was not an automobile in the modern sense. It had no engine, fuel system, or driver’s controls. Its likely purpose was theatrical: the cart may have been intended to create a dramatic entrance at court performances or festivals.

A full-size replica was built in 2006 by the Istituto e Museo di Storia della Scienza in Florence, now the Museo Galileo. The reconstruction moved as designed, supporting the interpretation that Leonardo’s mechanism was mechanically workable even though its range and control were limited.