Nothing challenges your brain like a Rubik’s cube puzzle. Matching the colors on each side can be both frustrating and rewarding when you finally do it. Making it all one color would be harder. Say, a brainy pink. Then add some actual brain details and this becomes an extra challenging puzzle.
Not only would this be hard, but you are constantly reminded of your brain, which is struggling. This design comes from Jason Freeny. It may be the grossest puzzle ever. Hopefully the texture isn’t all squishy and wet. Great puzzle for mad scientists.