Śatapatha Brāhmaṇa ("of a hundred paths") 7.4.1.44

7.4.1.44

te haike tiraścyā upadadhati | tiryañcau vā imau bāhū iti na tathā kuryātprācyāvevopadadhyātprāṅ hyeṣo 'gniścīyate 'tho evaṃ vai bāhū vīryavattarau te nānopadadhāti nānā sādayati nānā sūdadohasādhivadati nānā hīmau bāhū

Now some lay them down sideways (from south to north), saying, 'Sideways run these two arms (of ours).' Let him not do so, but let him lay them with the bowl towards the front (east), for this Agni (altar) is built with the head towards the front; and, besides, in this way the arms are stronger. Separately he lays them down, separately he 'settles' them, and separately he pronounces the Sûdadohas verse on them; for separate are these two arms.