Shatapatha Brahmana 10.5.4.5

10.5.4.5

nakṣatrāṇi ha tvevaiṣo'gniścitaḥ tāni vā etāni saptaviṃśatirnakṣatrāṇi saptaviṃśatiḥ saptaviṃśatirhopanakṣatrāṇyekaikaṃ nakṣatramanūpatiṣṭhante tāni sapta ca śatāni viṃśatiścādhi ṣaṭtriṃśattato yāni sapta ca śatāni viṃśatiśceṣṭakā eva tāḥ ṣaṣṭiśca trīṇi ca śatāni pariśritaḥ ṣaṣṭiśca trīṇi ca śatāni yajuṣmatyo'tha yānyadhi ṣaṭtriṃśatsa trayodaśo māsaḥ sa ātmā triṃśadātmā pratiṣṭhā dve śira eva ṣaṭtriṃśyau tadyatte dve bhavato dvyakṣaraṃ hi śiro'tha yadantarā nakṣatre tatsūdadohā atha yannakṣatreṣvannaṃ tatpurīṣaṃ tā āhutayastāḥ samidho'tha yannakṣatrāṇītyākhyāyate tallokampṛṇā tadvā etatsarvaṃnakṣatrāṇītyevākhyāyate tatsarvo'gnirlo

But, indeed, that Fire-altar also is the Nakshatras:--for there are twenty-seven of these Nakshatras, and twenty-seven secondary stars accompany each Nakshatra,--this makes seven hundred and twenty, and thirty-six in addition thereto. Now what seven hundred and twenty bricks there are of these, they are the three hundred and sixty enclosing-stones and the three hundred and sixty Yagushmatî bricks; and what thirty-six there are in addition, they are the thirteenth (intercalary) month, the body (of the altar); the trunk (consisting of) thirty, the feet of two, the (channels of the) vital airs of two, and the head itself being the (thirty-fifth and) thirty-sixth,--and as to there being two of these, it is because 'siras' (head) consists of two syllables;--and what (space) there is between (each) two Nakshatras that is the Sûdadohas; and what food there is in the Nakshatras that is the earth-fillings (between the layers of bricks), the oblations and the fire-logs; and what is called 'nakshatras' that is the space-filling (brick):--thus this comes to make up the whole Agni, and the whole Agni comes to be the space-filler; and, verily, whosoever knows this, thus comes to be that whole (Agni) who is the space-filler.