What did Leonardo da Vinci design as a driverless cart powered by wound springs?

Leonardo da Vinci designed a self-propelled cart powered by wound springs.

The cart was drawn in Leonardo’s Codex Atlanticus, probably around 1478–1480. Its springs stored mechanical energy, while cams helped control the wheels and steering. Unlike an ordinary wagon, it was intended to move without a person or animal pulling it.

The design is often described as an early programmable machine because its motion could be set in advance. The cart may have been intended for theatrical performances, where it could carry scenery or move across a stage. Its exact original purpose is not certain, however.

Modern reconstructions have demonstrated that the mechanism can work, although surviving drawings leave some details open to interpretation. It is sometimes incorrectly called the world’s first automobile; more precisely, it was a spring-powered automaton or cart, not a motor vehicle with an engine.