In Part 2 ("Apert") of Anathem, Erasmas was guiding a tour and was explaining the story of a statue of Cnoüs:
"The central sculpture was more than six thousand years old; it had been a world-famous masterpiece for almost that long. [...] It was Cnoüs, aged but muscular, with long, wavy beared and hair, sprawled back against the gnarled roots of a tree, staring up in awe and astonishment. As if it to shield himself from vision, he had raised a hand, but could not resist the temptation to peek over it. Gripped in his other hand was a stylus. Tumbled at his feet were a ruler, a compass, and a tablet graven with precisely constructed circles and polygons.
[...] Everyone else—even I, who'd seen it many times—looked up to see what was having such an effect on poor old Cnoüs. The answer (at least, ever since the statue had been installed here) was an oculus, or hole at the apex of the Rotunda dome, shaped like an isosceles triangle, and letting in a beam of sunlight."
"Cnous was a master stonemason," I began. "On one ancient tablet, which was made before he had his vision, he is described by an adjective that literally means one who is elevated. This might mean either that he was especially good at being a stonemason or that he was some kind of holy man in the religion of his place and time. At the command of his king , he was building a temple to a god. The stone was quarried from a place a couple of miles upriver and floated down to the building site on the rafts."
Is Stephenson making a blatant reference to freemasonry, is he making a biblical reference, or is Cnous's back story a coincidence to masonic symbolism? I can't find much on this portion of the novel.