[EricH]

Originally Posted by RRLedford

Well, my curved "atoll" frame effectively has no vertexes (or ALL vertexes), so it is NOT a polygon. Perhaps, a topologically proper string "wrap" should enter and follow around the shore the lagoon? I guess not.
It appears that the rules clearly are meant to discourage curves in general, and all but the shallowest of concave perimeter shapes in particular.
-RRLedford

As you're a rookie, be glad you're in this year's bumper debates instead of last year's. Last year's rules were almost the same, though with an allowed opening percentage, but the way they were written and a required piece of hardware (that had to be included in the opening percentage) practically forced a rectangular design. There was one case where a particularly tricky design to call had to be shown, Q&A by Q&A and rule by rule, where the interpretations of the GDC differed from the design. (Admittedly, this particular limitation had already been accepted by the team. Someone else was pressing the issue.) This year's are much easier, at least for those that were around last year.

And convex curves in general are not prohibited; see http://forums.usfirst.org/showthread.php?t=13723

As for concave perimeter shapes, the only place you can't have them is on the frame perimeter and anywhere you think a ball can get into the lower frame perimeter more than 3".

One thing I might suggest for next year's rules is the changing of the word "string" to either "stretched string" or "rubber band", as a number of people have thought the same thing.