He just sits there in the corner, stacking and unstacking them. Stacking and unstacking. Stacking and unstacking. It’s just like us bigger kids did with the Rubik’s cube. He’s trying to solve it, can’t quite figure it out, but can’t stop. But, this little toy doesn’t stop there. Unlike the Rubik’s Cube, which had two purposes—to play with and to chuck as far as you could into the lake when you could take no more—this toy has lots of other uses. When he’s done stacking, he makes them into balls and rolls them around. Then, he stands up and bangs them on the TV stand, scraping them back-and-forth to make a sound reminiscent of fingernails on a chalkboard (a sound that might otherwise go extinct as chalkboards go the way of the Commodore 64). Then, he crawls around for awhile with a couple of the cups in his hands like little suction cups, and starts all over again. He’s happy playing by himself or with his mom (me, not so much) for hours every day.