I made a robot that could replicate a painting (that you made using the robot). The robot was controlled by a Wacom tablet so it had 3 dimensions of input (x, y, and z for pen pressure). It was able to replicate its own paintings using just dead reckoning. Was fun programming custom Arduino code to drive the motors.

https://www.instapainting.com/blog/research/2015/09/10/robot...