Before the sun is up, a builder kneels on cleared ground with a coil of cord and a handful of wooden pegs. He drives one peg, ties the cord to it, stretches it taut to its full length, and swings the free end in an arc, scratching a faint curve in the earth. Then another peg, another arc; where the arcs cross, a point; and slowly, from nothing but a stretched string and the patience of the hands, a perfect square takes shape on the ground — the foundation of a fire altar, laid out to the exact proportions the ritual demands. There is no ruler, no protractor, no written number. There is only the cord, pulled tight between earth…