As a class assignment for Francis Bitonti and Xuedi Chen, students at the Architecture School of Rensselaer Polytechnic Institute built what they call the PiBot, a flexible, dual extruder 3D paste printer system which works in combination with a rotating, polar bed. Three students, Nicholas Nord, Hiroki Sawai and Lauren Famularo took up the challenge posed by Bitonti, a renowned architect, designer and researcher, and Chen, a Brooklyn-based designer and educator whose work spans industrial design, architecture, fashion, robotics and installation, for their build and design process. Taking a Printrbot Simple Maker's Edition unit and using the basic concepts behind that printer as their base to begin the work, they also used William Steele's PiMaker for inspiration. They call the result of their work "a flexible, dual extruder system." If you want to read more about the project, you can check it out here: http://3dprint.com/30675/pibot-paste-3d-printer/

Check out a photo of the PiBot printer below: