Alan Chatham of Unojoy wrote an Instructable on using pencil drawings as capacitive sensors:
Did you know? You can make pencil drawings reactive to touch for use with your projects! It’s really easy, and gives you a lot of flexibility in making interfaces for whatever microcontroller project you’re making.
Making a capacitive touch sensor from a drawing via Arduino
John Foster the maker and author of the fosterbot, a nice little 3D printer that was derived from the previously published Thing-O-Matic 3D Printer, just published his blueprints and instructables on Thingiverse for everyone who would like to make such a handy tool for himselve. He published all the necessary .dxf CAD files and a detailed description how to assemble such a 3D printer as well as good hints where to get the acryl panels laser cut. Its a real nice description to build a 3D printer for yourself, thanks a lot John!