My version of a gondola (penholder) for a simple vertical plotter. See also the bead chain gear in my objects. http://www.thingiverse.com/thing:467647 See both objects in action in this video: https://www.youtube.com/watch?v=LPdCCa383Jw There is also a slightly more complicated v4 here: http://www.thingiverse.com/thing:478346 These models (and some electronic stuff) are all you need to build your own vertical plotter. Sandy Nobles (creator of Polargraph) great Instructables is a good point to start: http://www.instructables.com/id/Polargraph-Drawing-Machine/?ALLSTEPS This is iteration 3 of the gondola. Far from perfect, still a work in progress. Features: You can see some more pictures here (text in german, sorry): http://www.makerblog.at/2014/09/vertikalplotter-im-selbstbau-teil-1-polargraph-kritzler-makelangelo-und-co/