What wheeled invention by Leonardo da Vinci is often called an early self-propelled cart?

Leonardo da Vinci designed a self-propelled cart that is often regarded as an early programmable machine.

Leonardo drew the cart in the Codex Atlanticus, probably around 1478 to 1480. Unlike an ordinary wagon, it was powered by coiled springs that drove the wheels. Programmable elements, including pegs on the wheels, could determine the cart’s movement and steering.

The cart may have been intended for theatrical performances or court spectacles rather than transportation. Its compact mechanism could make the vehicle move forward without an animal or person pulling it. Because the original drawing is incomplete and its exact operation has been reconstructed from surviving evidence, some details remain interpretations rather than certain facts.

Modern replicas have demonstrated that the basic mechanism can work. The cart is sometimes called a “robot,” but that label is retrospective. It did not have artificial intelligence or independent perception. Its historical importance lies in combining stored mechanical energy, wheels, and programmable motion in a remarkably early design.