Leonardo da Vinci designed a self-propelled cart that could move without a person pushing it.
Leonardo drew the cart in the Codex Atlanticus, probably around 1478 to 1480. Coiled springs stored energy inside the machine, while a system of gears transferred that energy to the wheels.
The cart could be programmed to follow a predetermined path through a steering mechanism. This made it an early example of a programmable mechanical device, although it was not an engine-powered vehicle in the modern sense.
The drawing was not fully understood for centuries because some details were hidden by overlapping components. In the twentieth century, researchers built working replicas and demonstrated that the mechanism could move. It is sometimes called Leonardo’s robot car, but “self-propelled cart” more precisely describes the design.