This starts out easy, but every time you successfully complete one of the all-white puzzles, you get another one with more pieces. I can't seem to stop playing... I want to know how large the final puzzle gets! If anyone gets there, let me know.
Link
Also: I want the Beatles White Album puzzle...
http://ngm.nationalgeographic.com/your-shot/jigsaw-puzzles
You can optionally rotate the pieces and set the number of pieces to make it harder.
http://www.digyourowngrave.com/white-jigsaw-puzzle/
Is there any way to save your game so you don't have to replay when you go back?