Make your own bot that doodles different patterns
A Scribbler Bot is a machine powered by a motor, that movies in unusual ways and makes wonderful patterns by tracing its path. It's made from simple materials ansd shows the erratic motion that can be created by an offset motor.
Try changing the offset length, height and weight of the motors, testing various drawing tools, experimenting with materials used for the base, and increasing and decreasing the speed of the motors. You will be amazed at the different motions and patterns you can create.