What self-moving vehicle did Leonardo da Vinci sketch that is often called the first programmable machine?

Leonardo da Vinci sketched a self-propelled cart powered by coiled springs and guided by programmable controls.

The cart appears in drawings dated to around 1478–1480. Two large springs stored energy, while a system of gears transferred that energy to the wheels. A programmable device, compared with a modern cam mechanism, could determine the route by controlling the steering.

The cart may have been intended for theatrical performances or court ceremonies rather than transportation. It could move without a person pushing it, which makes it an important early example of an autonomous mechanical vehicle.

The cart is frequently called the world’s first automobile, but that wording can be misleading. It had no combustion engine and could travel only a limited distance using spring power. In 2006, Italy’s Institute and Museum of the History of Science built a working replica to test Leonardo’s mechanism.