Matsya Purana 264.16

264.16

caturbhistoraṇairyukto maṇḍapaḥ syāccaturmukhaḥ.
plakṣadvāraṃ bhavetpūrvaṃ yāmye caudumbaraṃ bhavet .. 264.15

There should be 4 doors with archways round the Maṇḍapa and of those the eastern door should be of Plakṣa tree, the southern one of the fig tree the western one of aśvattha tree and the northern one of Nyagrodha tree The Maṇḍapa should be buried 1 hand in the ground and it should be 4 hands in height.—15-16