Leonardo da Vinci designed a self-propelled cart powered by springs, gears, and a programmed steering mechanism.
The cart appears in drawings from around 1478 to 1480. Large coiled springs supplied energy, while gears transferred that energy to the wheels. A system of blocks set the steering path, allowing the cart to follow a predetermined route rather than being continuously guided by a driver.
The device is sometimes called Leonardo's automobile, but it was not an automobile in the modern engine-powered sense. It had no combustion engine and was intended for short, controlled movement. Researchers have proposed that it may have been designed for theatrical displays at court.
A working reconstruction was displayed in Italy in 2006. The reconstruction helped demonstrate that the surviving drawings could describe a functioning mechanism, although some details had to be inferred because Leonardo's sketches do not provide a complete modern engineering plan.