Anything that's impossible to solve? Or something hard? Here's mine: the 14-15 puzzle. Is it possible? No. If you have no idea of what i'm talking about, follow this link//en.wikipedia.org/wiki/Fifteen_puzzle
I already solved it about 100 times, then I got bored so I moved onto the 3x3. All puzzles have some sort of solution, if it didnt, then it would not be a puzzle.
