Atharvaveda 9.10.19

9.10.19

r̥cáḥ padáṃ mā́trayā kalpáyanto 'rdharcéna cakl̥pur víśvam éjat |
tripā́d bráhma pururū́paṃ ví taṣṭhe téna jīvanti pradíśaś cátasraḥ ||19||

Shaping (kalpay-) with measure the step of the verse, they shaped by the half-verse all that stirs; the bráhman of three feet, many-formed, spread out (vi-sthā); by that do the four quarters live.