I know when I first saw a picture of the space wheels when I was kid I didn't know then that it was two sky wheels side by side. In the picture one unit was in the up right position (loading), the other was coming down just at the half point and I thought it was one unit had four wheels. Now wouldn't that be something? I was kid, and soon find out later how it really was. But neat to hear some of this information on here about the sky wheels.