I know this might sound silly to you e-engineers, but I've been wondering this one thing. Since triangles seem to kick all sorts of arse in terms of structural strength (prob. not the correct term), why aren't bicycle tubes simply made this way? I mean, tubes could be hydroformed, or in the case of carbon fibre, somehow molded into a triangular shape, resulting in a theoratically stronger tube. I know there's probably some simple reason preventing it, but I just can't figure it out.