Here are some images of Academy Minicraft's Leonardo da Vinci's Self Propelled Cart.
From Leonardo da Vinci's Inventions"
Before motorized vehicles were even a glimmer in someone’s eye, Leonardo da Vinci designed a self-propelled cart capable of moving without being pushed. Among its other accomplishments, many consider da Vinci self-propelled cart invention to be the world’s first robot.
The self-propelled cart was one of the many inventions that Leonardo created dealing with locomotion and transportation. Historians later deduced that da Vinci specifically designed the cart for theatrical use.
Leonardo’s cart was powered by coiled springs and it also featured steering and brake capabilities. When the brake was released, the car would propel forward, and the steering was programmable to go either straight or at pre-set angles.
Da Vinci’s cart design was so ahead of its time that its exact workings baffled scholars until late in the 20th century. But, in 2006, Italy’s Institute and Museum of the History of Science in Florence built a working model based on da Vinci’s design and, to the surprise of many, the cart actually worked. Some experts even noted that it looked similar to the Mars Land Rover.