**Pre-order (Ships in 2-3 Weeks)** Rainbow Musical Ball Run Assembly SetThe children may build up this ball run by themselves, sorting the colors at their discretion. One can also have marble races, which result in a double spiral run. For example, you let run a wooden bead against the included bell. Who will be the winner? Which ball is the quietest running down the path? Which one makes the most noise? After a while, the ball run can be dissembled and arranged in a different color set up, so the fun starts again.