Shatapatha Brahmana 6.5.3.3

6.5.3.3

athokhāṃ karoti | imāṃstallokānkarotyatha viśvajyotiṣaḥ karotyetā devatā agniṃ vāyumādityametā hyeva devatā viśvaṃ jyotistā etasyā eva mṛdaḥ karotyebhyastallokebhya etāndevānnirmimīte yajamānaḥ karoti tryalikhitā bhavanti trivṛto hyete devā ityadhidevatam

Now he (the Sacrificer) makes the fire-pan: he thereby makes these worlds. He then makes the (three) 'all-light' (bricks), that is these deities, Agni, Vâyu, Âditya, for those deities indeed are all the light. He makes them from that same clay (as the fire-pan): he thus produces these gods from these worlds. The Sacrificer makes them. They are marked with three lines, for threefold are these gods. Thus as regards the deities.