Vedic 21 + 21

A child can see a house fire that must not go out. A householder kindles it at marriage, Agnyādheya, and tends it morning and evening, Agnihotra, for the rest of a life. The bricks are the body of that fire. First layer: three by seven, twenty-one. Second layer: twenty-one again, turned, so the seams do not stack. The Brāhmaṇa says why twenty-one: twelve months, five seasons, three worlds, and the sun. Eggeling, Śatapatha 7.1.1.34. Taittirīya Saṃhitā 5.2.3.5. Baudhāyana Śulba 7.4–7.7. 21 is the named integer. 42 is two layers of the named count. Staal filmed the great bird altar. That is a later, larger fire, Agnicayana, two hundred bricks a course. The household hearth is the one that lives in the day.

Not Sacred Books of the East volume 12. The hearth kanda is Eggeling’s SBE 41. Not five layers of twenty-one, which some later manuals also know. Not Gītā 3.42 or 4.42. Not Numbers 33. Forty-two wilderness stations are a journey list, not a brick count. Both are rites that count. They did not hire each other.

21 is named first. Two layers make 42 in the construction. Five layers are another manual.