Skeleton Most of the skeletons in origami feature articulated rib cages. The only practical way of avoiding the thickness generated by so many appendages is to use more than one sheet for the structure. This work avoids that problem by using a single appendage for each set of ribs, and using pleats to imply distinct appendages. Although the limbs use box-pleating techniques, the ribs do not, so some interesting folds occur at the various junctures. Purchase diagrams at Lulu.com