It's a bunch of little plastic not-quite-pyramids with magnets in them that you can assemble in a variety of ways but the default organized state is a ball. The one at the register at Little Towne Toys (which we love) was partially unassembled until T. got to it. I had to wait a very brief amount of time after the transaction was completed and the toys were bagged for him to finish, but he was quick and methodical and completely unfrustrated. It was cool and amazing and awesome -- and it looked just like the picture when he was done. A picture I am uncertain whether he has ever noticed.
We stopped at McDonald's on the way home and I handed him the change to put in the little charity box in front of the register. He's always liked putting tokens into slots; this is just one more opportunity to distract him from waiting with an enjoyable pastime. This time, however, he counted each coin as he put it in. Very, very quietly, and accurately, all seven of them. He wasn't doing this to impress _me_ -- if he had, he'd have been yelling. When I told R., R. said he saw T. counting his fingers yesterday or perhaps the day before.
Weirdly, I think I find the counting more exciting than the whacks ball, altho objectively, the whacks ball is more impressive.