Śatapatha Brāhmaṇa ("of a hundred paths") 3.5.3.9

3.5.3.9

tayoḥ samavavṛttayoḥ | cadiradhinidadhati yadi cadirna vindeyuścadiḥsammitām bhittim pratyānahyanti rarāṭyām pariśrayantyucrāyībhyāṃ cadiḥ paścādadhinidadhati cadiḥsammitāṃ vā bhittim

Over them, having been turned round (and placed on the altar), they put a mat of reed-grass; or, if he cannot procure a reed-mat, a frame of split cane made in like manner as a reed-mat. They fasten a front-band (to the posts of the front door). They enclose (the carts) within two upright hurdles; and lay a (second) reed-mat, or a frame of split cane made in like manner as a reed-mat, behind (the first mat).