Apastambashulbasutra 290.1

290.1

ātmani purastādbhāge ṣaṭtriṃśadaṅgulāyāmena kāritādyārdhāḥ pratīcīḥ pratyagāyatāḥ daśopadadhāti /
ātpranyeva paścādbhāge tā eveṣṭakāḥ tatsaṃkhyākāḥ prācīḥ -- prāgāyatāḥ /

In the body of the altar, in the eastern part, he places ten one-and-a-half bricks made with a length of thirty-six finger-breadths, facing west—extended westward. / In the body of the altar itself, in the western part, [he places] those same bricks of the same number, facing east—extended eastward.