What wheeled device did Leonardo da Vinci sketch as an early programmable mechanical vehicle?

Leonardo da Vinci sketched a self-propelled cart as an early programmable mechanical vehicle.

The cart appears in a drawing from about 1478–1480. It was powered by coiled springs hidden inside its body, with the stored energy transferred to the wheels through gears. Programmable control came from shaped cams: by arranging the cams, an operator could determine how far the cart traveled and whether it turned. The device may have been intended for theatrical performances or ceremonial displays rather than transport.

The cart is often described as a robot because it could move without a person riding or pushing it. That description is useful historically, but it was not an autonomous robot in the modern electronic sense. A reconstruction made in the early 21st century demonstrated that the mechanism could work when built according to the surviving drawings, although some details remain interpretive because Leonardo’s notes are incomplete.