What mechanical cart is often called Leonardo da Vinci's earliest programmable machine?

Leonardo da Vinci designed a self-propelled cart often called an early programmable machine.

The cart was drawn in the Codex Atlanticus and is generally dated to the late fifteenth century. Springs wound by hand supplied its stored energy, while a system of gears transferred that energy to the wheels. Steering could be set in advance with pegs placed in a programmable mechanism, allowing the cart to follow a predetermined path.

The design is sometimes described as a robot because it could perform a programmed movement without a person riding inside it. That label is modern, however. Leonardo did not call it a robot, and the word robot was not coined until the twentieth century. It is more precise to call the object a self-propelled cart or mechanical vehicle.

A reconstruction built in the early twenty-first century showed that the design could operate when assembled according to the surviving drawings. The cart is unrelated to Leonardo's mechanical lion, another automaton associated with court ceremonies and later reconstructions.