A new project being developed at the University of Tokyo is producing incredible and complex architectural structures using a 3D printing pen. It has been modified to work with the user to create precise and stable structures only using extruded plastic. These "large-scale hand-drawn structures" are made by manually connecting acrylic rods with strings of thermoplastic filament that are guided into place using a custom designed 3D digital tracking system. Due to the temperature of the pen, the acrylic rods and the plastic filament bond together virtually instantly and can be used to create large structures that offer excellent stability and will typically last for about nine months. You can learn more about these amazing structures on 3DPrint.com: http://3dprint.com/121439/tokyo-u-3d-pen-structures/