And this is what we're after, a relatively even octagonal shape for the length of the spar. Now that I have this, it's time to knock off the corners again to get closer to a circle. For a really big mast, another spar maker's guage would be used to mark off yet another set of triangles to achieve 16 sides, then 32, and so on, but now that I have an octagon, I'll just shape it by eye. Not that I'm terribly confident in my ability to do things by eye, but I have no patience for drawing all those lines again. Oh, one other thing, if you do decide to go for another set of lines, the dimensions are different for going from 8 to 16 sides, and different again for 32.