Śatapatha Brāhmaṇa ("of a hundred paths") 6.1.2.30

6.1.2.30

tadāhuḥ | yadevamekeṣṭako 'tha katham pañceṣṭaka itīyaṃ nveva prathamā mṛnmayīṣṭakā tadyatkiṃ cātra mṛnmayamupadadhātyekaiva seṣṭakātha yatpaśuśīrṣāṇyupadadhāti sā paśviṣṭakātha yadrukbhapuruṣā upadadhāti yaddhiraṇyaśakalaiḥ prokṣati sā hiraṇyeṣṭakātha yatsrucā upadadhāti yadulūkhalamusale yāḥ samidha ādadhāti sā vānaspatyeṣṭakātha yatpuṣkaraparṇamupadadhāti yatkūrmaṃ yaddadhi madhu ghṛtaṃ yatkiṃ cātrānnamupadadhāti saivānnaṃ pañcamīṣṭakaivamu pañceṣṭakaḥ

As to this they say, 'But if he (Agni) thus consists of one brick, how then (comes he to be) a five-bricked one?' Now surely the first brick of clay is this earth,--whatever made of clay he places on that (altar) that is that one brick. And when he puts thereon the heads of the animal victims, that is the animal-brick. And when he puts on the gold plate and man, when he scatters gold shavings thereon, that is the golden brick. And when he puts on two spoonfuls (of ghee) when he puts on the mortar and pestle, and fire-sticks, that is the wood-brick. And when he puts on a lotus-leaf (petal), a tortoise, sour curds, honey, ghee, and whatever other food he puts on, that is the fifth brick, the food. Thus, then, it is a five-bricked (Agni).