Instructions
You will need six to make a box.
All the locking tabs at a single join work perpendicularly to the join, so you should be able to assemble two box halves, then clip the halves together.
EDIT: I *STRONGLY* recommend using the later version of this, this version is not a manifold mesh and Skeinforge won't process it correctly. You can get the corrected version here:
thingiverse.com/thing:500




