What self-propelled machine did Leonardo da Vinci design for theatrical events?

Leonardo da Vinci designed a self-propelled cart that could move without being pushed by a person or animal.

The machine used coiled springs to store energy. When released, the springs drove the cart’s wheels through a system of gears. Steering could be set in advance, allowing the cart to follow a predetermined path. Leonardo likely intended this type of machine for theatrical performances, where it could create the appearance of an independently moving object.

The cart is sometimes called Leonardo’s automobile, but that label can be misleading. It did not have an engine, fuel system, or driver like a modern car. It was a mechanical automaton powered by stored spring energy. Leonardo’s original drawing dates from the late fifteenth century.

A working reconstruction was made in the twentieth century and demonstrated that the basic mechanism could operate. The cart is therefore one of Leonardo’s more testable mechanical designs, even though no original vehicle survives.