drawing robot research

http://juerglehni.com/works/hektor/
http://academy.cba.mit.edu/content/tutorials/akf/drawbot.html
https://www.thingiverse.com/thing:472573
http://tinkerlog.com/2011/09/02/der-kritzler/
https://www.thingiverse.com/thing:661395
http://makezine.com/projects/trs-drawbot/
http://makerblock.com/2013/02/building-a-drawbot-on-the-cheap/

https://github.com/MarginallyClever/Makelangelo
https://www.marginallyclever.com/shop/drawing-robots/
http://learn.marginallyclever.com/index.php/Makelangelo_2_Software
https://github.com/euphy/polargraphcontroller
https://github.com/tinkerlog/Kritzler
https://github.com/euphy/polargraph
https://github.com/yosemitebandit/erik
https://github.com/MarginallyClever/GcodeCNCDemo

http://learn.marginallyclever.com/index.php/GcodeCNCDemo
https://github.com/MarginallyClever/gcodesender