[patbarry]

Not being an expert, but when has that ever stopped me before...Maybe it's two and the intersection of the beams is where the fracture takes place. I remember doing a job at NASA once and they had this really cool machine that made mock-ups of various parts. A lasar was focused on a bed which was submersed in a special liquid. As the lasar traced out the pattern, the liquid was turned to a solid and the bed was moved lower and lower into the liquid as the part was built up. Very neat. I think I watched for something like an hour before being chased back to work. I'm not sure that this lasar would have created a rod if allowed to shine all the way through the vat if the bed was removed, or if it focused specifically at the plane where the bed sat. Probably way above my head for understanding. Neat stuff, though.