What mechanical device is Leonardo da Vinci credited with designing to move without an animal?

Leonardo da Vinci is credited with designing a self-propelled cart to move without an animal.

The drawing, made around 1478–1480, shows a compact three-wheeled vehicle powered by coiled springs. As the springs unwound, stored energy would turn the wheels through a system of gears. A steering mechanism could be set before the cart began moving, allowing it to follow a planned path.

The cart was probably intended for theatrical performances or ceremonial displays rather than ordinary transportation. Leonardo’s notebooks contain many mechanisms for stage effects, military engineering, and machines, so the cart should not automatically be treated as an early automobile.

A reconstruction in the late twentieth century showed that the mechanism could work when built according to the surviving drawings. The vehicle had no engine in the modern sense; its motion came from mechanical spring power. That distinction is why “self-propelled cart” is a safer historical description than “car.”