Polargraph Retractable Pen Head

A design for a Polargraph machine (http://www.polargraph.co.uk/) retractable pen head and gondola.

The goal was to create a gondola that could take the pen off of the drawing surface without moving the entire unit. What is lost from the classic Polargraph design are the pivoting arms that ensure that the pen is always at the center point of the two belts suspending the pendulum.

In my version, I laser cut out of plexiglass the round hubs of the gondola and the spacers between the hubs. In