A favourite for my 5 and ups. But "2 sided" puzzles are confusing for the young children. I'd like to be able to save as a default config for the children the "-side 2" switch to force all of the pieces to be flipped over to side 2 at the beginning so they don't have to manually flip them over. Also, I'd like to be able to disable the middle-mouse-button mapping to flip pieces, as they sometimes accidentally hit it, much to their puzzlement (no pun intended) and frustration. A gui-based puzzle launcher that allows the child to point-and-click to choose the puzzle image and size would be great.