Gretels Revenge

Gretel is angry because of Hansel's airs of superiority and condescension. She gives him a test to prove his skills by solving a special puzzle. Every jigsaw piece consists of two labeled ends - left and right. No piece of the puzzle can be flipped over. The pieces can be A or B slotted and both the left and right slots of a single piece need not be of the same type. For example, a piece AB contai