Roy Repp was an Australian stunt driver. One of his stunt cars was Maude the Motor Mule. For this car, he would pull a lever, and a heavy weight beneath the car moves forward or backward to shift the center of gravity and makes the car rear up on its hind wheels or front wheels.
![Roy Repp and his Stunt Car](https://monovisions.com/wp-content/uploads/2015/02/Roy-Repp-bucking-Buick-Maude-Motor-Mule-1915-04-1040x440.jpg)