Does your Dad have everything? Even a box to put it all in? Well, here's something he probably doesn't have - Constantin: Double Trouble puzzle. Just one of the deviously tricky and beautifully crafted puzzles that come from the mind of Jean Claude Constantin.
The object of Constantin: Double Trouble puzzle is to extract both balls from their mazes at the same time. The problem is, the mazes are linked together with cog teeth. Move one, and the other moves too. Constantin: Double Trouble puzzle will keep Dad quiet for hours!
Check out Puzzle Guy's proof that this can be done: YouTube