Matsyapurana 93.94

93.94

tasya cottarapūrveṇa vitastitrayasaṃsthitam
prāgudakplavanaṃ tacca caturasraṃ samantataḥ //

To perform the sacrifice of a lac of offerings, a sacrificial pond of 4 hands in length and 2 in breadth should be made. Its mouth should be made of the shape of a conical-triangle. Three girdles should also be made to surround the pit.—93. To the north-east of the pandal, after leaving a space of three vitastas, the sacrificial pond should be dug. On the land selected for it, a square altar slanting north-east should be erected.—94.