2-in-1 challenge puzzle   This 2-in-1 puzzle can be assembled in two distinct ways. We created it by growing a puzzle around a puzzle. In addition to the 2-in-1 feature we made it extremely challenging by removing all the things that normally help you assemble a puzzle. There are no edge pieces and no image. 2-in-1 Challenge Puzzle -- 15x13" rectangle and 7" circle with approximately 410 pieces