This achievement is for the bonus puzzles that can be unlocked if you assemble the secret map in the game. For whatever reason, they're all different iterations of the same puzzle: Move the crystals around until none of the beams are crossing. It mostly relies on spacial reasoning to solve, so if that's a weakness for you, then this guide can help you get your bearings.

If any of these screenshots are too confusing or unclear, let me know and I'll get you a better one, since these are all shots of my first try and I know a few could be cleaner.