I've seen some rocks recently that are made in such a way, that there's extra fabric on one side, kind of like a ribbon, or something, going for about maybe 10 inches. Its long enough to swing the rocks, some folks have sworn it improves distance to hold it by the streamer and throw it that way, kind of like using it as a sling.
It technically is still only foam and cloth, and of proper diameter.
I was wondering if there were any unofficial national level rules about that? Is it common, is it accepted at national level events? If it is allowed by that, how long can the streamers be?
Edit: Thanks for the info, and I so totally agree.