A popping polyhedron powered by rubber bands. Folds flat and pops into its 3D form when released. It's fully parametric and includes filament hinges that can be used in other projects. You can see a seven second movie of it here: https://dl.dropboxusercontent.com/u/1775688/popbox.m4v If you want to use the hinges in another project, go see my Hinge Variations http://www.thingiverse.com/thing:266956.Makes a Pop Box: a six faced object with rubber bands inside that can be flattened to a half-hexagon shape and will pop-back into a three-dimensional shape. As well as the print, you'll need two small rubber-bands. The hinge pins are filament. Before printing all six faces, pick out some 1.8mm diameter filament for use as the hinge pins and print just one face. Check that the inside diameter of the hinge with the three parts is a tightish fit for the filament. It should be tight enough to grip it, but not so tight that you can't get it in. The inside diameter of the hinges with two parts is slightly larger to allow that hinge to rotate freely. A simple fix for filament that is too large is to slim it a little with sandpaper and shape the end into a point so it more easily slips through the hinge holes. Once you have found suitable filament, or adjusted the inside diameter appropriately, print all six faces. As provided the faces are 1.4mm thick and 50mm on a side. The hinges are 5mm diameter. You can go with a thickness as low as 1mm and drop the hinge size to 4mm. If you make large faces, increase the number of hinge sections, keeping it as an odd number. Compile popbox.scad in OpenSCAD and export as STL. You'll need the other two SCAD files in the same folder as popbox.scad. I've successfully printed a number of these in PLA at 0.2mm layer height. Assemble the top three faces in the row, inserting filament in the hinges and cutting it flush. Assemble the bottom three faces in the row, again inserting filament and cutting it flush. Assemble the top three and bottom three together at the middle triangle, but leave about 4mm of filament sticking out at both ends. These will anchor the rubber bands. Assemble both ends, this time leaving 4mm filament sticking out at the open end of the Pop Box only. These two ends will anchor the other ends of the rubber bands. Push a rubber band in through the slot in the back and anchor it at one end. You will need to force it between the filament and the triangle face. Open the Pop Box part way and pull the rubber band diagonally across and hook it onto the filament sticking out of the opposite side. Force it down between the filament and the face.