Śatapatha Brāhmaṇa ("of a hundred paths") 7.4.1.35

7.4.1.35

paścādagneḥ prāṅāsīno | 'thottarato dakṣiṇātha purastātpratyaṅṅatha jaghanena parītya dakṣiṇata udaṅṅāsīnastaddakṣiṇāvṛttaddhi devatrāthānuparītya paścātprāṅāsīnastatho hāsyaitatprāgeva karma kṛtam bhavati

Behind the altar (he offers) while seated with his face towards the east; then on the left (north) side (looking) to the south; then in front (looking) to the west; then going round behind, (he offers) on the right (south) side while sitting with his face towards the north. Thus (he moves) to the right, for that (leads) to the gods. Thereupon, going back, (he offers) while sitting behind, with his face towards the east; and in this way that performance of his takes place towards the east.