we made a draw robot. the purpose of it was to make a robot that, surprise, draws. mine was not very good even though i went into it knowing it would be bad at drawing. a couple times it drew straight lines or drew a perfect circle. the materials we used were a tooth brush, a cup/multiple cups, and a marker/multiple. mine originally had multiple markers and multiple cups but i changed it down to one eachand it made betterlines and circles.