The incredible inner workings of the human body are beautifully portrayed in this double - sided educational floor puzzle. One side of this 100 - piece cardboard puzzle features the skeletal structure, and the other side shows internal organs and the circulatory system. 4' long when assembled, the 100 extra - thick pieces are 20% thicker than the competition's. Its easy - clean surface keeps puzzle looking new. Children will be fascinated by this challenging, kid - sized floor puzzle.