Going off the rails

I got B1 a Skyrail marble run set back in Christmas of 2009, which he enjoyed for awhile, but hasn't played with for a long time. Anyway, he started playing with it again over the weekend, and it's cute, especially since B2 is now old enough to be able to play with it, too. So, they're busy crafting their own marble runs, and I hear B2 saying "Okay, let's test it!" Loving that. They had me make them a loop in the rail, and have crafted a track that lets it work. It's nice to see them working together, instead of the usual brotherly scrapping! And I just enjoy seeing new life for the toy, and how much fun they're having with it, launching marbles and ball bearings down their tracks. B1 also made one into a ring and had marbles going down both sides, said "Look, it's a supercollider!" I loved that!