I have always enjoyed magnetic toys, and now have quite a collection which my grandchildren and other visitors enjoy when they visit. This magnetic cube, though, is in a league of its own. I am a physicist, and have always enjoyed logic, symmetry, and novelty, and this has not disappointed. It is compulsive, and a delight to handle. There are very many ways of sticking the 216 balls together - the problem usually is preventing them from doing their own thing - and many of the results are quite beautiful. The 6x6x6 cube is the most symmetrical, and it took me quite a while to work out how to ensure it finished up as that satisfying cube, without collapsing on me during the process. When you discover it, it becomes surprisingly straightforward, but non the less satisfying. If you like scientific toys, this is a must have item. One surprise - the 216 (6 cubed) balls allow you also to make three cubes, of side 3, 4 and 5 balls. They also add up to 216 balls.