Few toys have become as ubiquitous as the Rubik’s cube. I have three in my room, a 3×3, a 4×4, and a 5×5. The cube has become one of the most desirable objects, I believe, because it appeals to a wide range of demographics. Young kids understand the objective. Teenagers often attempt to learn algorithms to solve it. It’s at once a fun toy and a mathematical puzzle. And once the puzzle is complete, it’s just as fun to redo it–unlike many puzzles that already exist.