Robotic pressure
Hektor is a spray painting robot. It consists of a spray can and "trigger" assembly suspended on two long lines connected to two motors on the upper corners of the canvas. By varying the speed and direction of each motor as well as activating the trigger, Hektor can paint a wide variety of scenes. What is even more impressive is that, according to the PDF on the site, Hektor has it's own path finding algorithm to know how to execute the art. Also be sure to check the movie [no direct link]. An impressive project.