[Wayne TenBrink]

It looks like a support for parallel bars (rails) that balls could roll on. The shallow slope (see below) would require a low rolling coefficient of friction in order to be gravity driven. It would require a ball of a particular size that was quite hard and smooth. Something similar to a moon rock or even the 2006 foam ball wouldn't roll on something this shallow. It would take something like a basketball or (I shudder to think!!) a bowling ball.

Quarter-inch lexan would be tough enough to handle the sort of contact you get in an overhead structure. It doesn't appear strong enough to take the impact of a 120 lb robot at full speed.

BUT - This is too easy. I doubt the GDC would release a clue that identified the size, shape, and "texture" of the game piece. I suspect trickery! It may be a field element, but I doubt that it is for moving the game piece (directly).

How much clearance is there between the "top" of the tube (as shown on FIRST) and the underside of the lexan bracket? If the rails held some sort of cart (like a car on a roller coaster with tubular rails), would there be enough space for some sort of "keeper" (something that would keep the cart from getting knocked off the rails) to pass between the tube and the bracket? Why else would the rails be held from the outside and not at the point nearest the tab on the bracket?

Note regarding the slope: Look at the radius of the bend in the "lexan" bracket. It isn't uniform - it forms a conical shape that is wider at the bottom.