The production of a bird cage from a comparatively small production box is very impressive since the total volume of the produced shining rigid metal bird cage(s) is far larger than the volume of the production box.
 
This bird cage is 5" on all sides and only 1 and 1/4" high when collapsed.  This can theoretically allow for four 5" square bird cages to be produced out of a 5" square production box (or 5" diameter circle)!
Sponge bird not included.