The bottom and the top of a 37-piece 8 1/2" x 11" x 1/8" highly interlocking puzzle based on a 37¢ (!) postage stamp with the backside of every other edge, "interior edge," "interior interior edge" etc. piece painted blue, light blue, light light blue etc. The cutting pattern was built from the inside out with each new piece bigger and "wobblier" than the last.