Puzzles have recently become popular at my house. We've finished two in the past month or so. We know we finished because the puzzles had a standard border and we filled in all the pieces creating a picture. The Infinite Galaxy Puzzle has no edges and no way to determine if you've finished because the pieces can be flipped and put in other areas of the puzzle. It's literally never ending -- thus the word "infinite". It can be assembled in thousands of different ways. The puzzle also features special space themed whimsy pieces; an astronaut, space shuttle, and satellite. Contains 133 laser cut birch plywood pieces.