Which Way

I'm a little slow getting a post today, because the first priority of the day was to get about 4" of that famous Utah powder cleaned off the drive and walks.
That Surplus Center place in Nebraska had a "grab bag" special on pneumatic cylinders; 10 for $20, their choice. So I placed an order, I like surprises. When the package arrived it was opened and one of the Bimba cylinders had a rod sticking out both ends. I thought what will I ever use that thing for. Then all of a sudden the little light blinked on in the attic. How about a double ended engine?

I already had a flywheel pattern that would work, and being symmetrical it only required a couple new ones. It has a rotary valve that rocks through an arc of 90 degrees, operated from a crank on the right end. The wheels on the right always turn the same direction, because they are timed with the valve, but the ones on the left can rotate either direction, depending on which way they get started. What is it good for? Like most of the other stuff I build, nothing,---except perhaps a bit of amusement.
Birk