Hello! This is my first post of the polargraph I built about a month ago. It is a rather normal and unexciting polargraph except for the fact that it cost me $30! As a student I am on quite the budget and so built it with whatever I had. The biggest discoveries I have made are that lego wheels once drilled out can be coupled with string to replace the beaded chain and sprockets. I used a blank cd back to act as the face of the gondola and just used some PVC I had lying around. While I am only limited to a normal sheet size the quality of drawings with normal ultra fine sharpie's is remarkable.You can see the results here:
http://www.youtube.com/watch?v=v-wrC-6wuE8

I just want to say what an amazing project this is and I can't tell you how many people have told me so, well done Sandy! I commented on your instructable and you left me a very nice comment back. This project inspired one of my own so feel free to check it out here:http://www.instructables.com/id/Window-Painting-Robot-arduino-controlled/.

Not as cool as a polargraph but something unique.