SD300 Mizzing Piece puzzle

This is designed for PVC laminated-object-modeling 3D printers, but it may work in flexible materials on other machines (possibly nylon).

The SD300, SD300 Pro, and Invision LD printers build a \"test part\" that folds up and snaps together into a nice little pyramid. I designed foldable_oct.stl to enable five standard test parts to be stacked to build a larger pyramid. The puzzle is to figure out how to utilize the new piece to make it possible.

NOTE: foldable_tetra.stl is equivalent to the SD300\'s standard test part, but it has a round hole that makes it easier to assemble and disassemble the parts. You don\'t need it if you\'ve got enough test parts lying around, but it\'s nice to have if you want to un-snap the pieces.