Matsyapurana 93.89

93.89

śobhanaṃ kārayetkuṇḍaṃ yathāvallakṣaṇānvitam
caturasraṃ samantāttu yonivaktraṃ samekhalam //

The altar should have a slant towards north-east, and it should be made with great care. The same north-east corner of the pandal, should be selected for the purpose of digging the fire pit. This pit should be a square, beautiful and according to rules. The pit should have girdles round it and of the form of the mouth of a yoni.—88-89.