It is a source of much frustration around the world, so much so that even some of our most qualified puzzlers just don't get this puzzle. Rocket science it is not, but human brains don't seem to react well to this tough little challenge.
Ultimate Metal Puzzles - The Enigma
Puzzle Mission - To separate the two pieces then reattach
Bemuse and amaze friends and family with this tricky 'Mind Muddler'!
Another great puzzle from Professor Puzzle
Difficulty level 2