Śatapatha Brāhmaṇa ("of a hundred paths") 8.2.1.18

8.2.1.18

yadvevaite atropadadhāti | prajāpatireṣo 'gniḥ saṃvatsara u prajāpatistasya yadūrdhvam pratiṣṭhāyā avācīnam madhyāttadasyaiṣā dvitīyā citistadvasya grīṣma ṛtustadyadete atropadadhāti yadevāsyaite ātmanastadasminnetatpratidadhāti tasmādete atropadadhāti

And, again, as to why he lays down these two in this (layer). This fire-altar is Pragâpati, and Pragâpati is the year. Now that (part) of him which is above the feet and below the waist is this second layer; and that same part of him is the summer season. Thus when he lays down those two in this (layer), he thereby restores to him that (part) of his body which these two ale: this is why he lays down these two (bricks) in this (layer).