The Vastu Purusha Mandala
The mandala assigns the four intercardinal corners to four of the five elements — water to the north-east, fire to the south-east, earth to the south-west, air to the north-west — and leaves the centre to space. The four cardinal directions carry a guardian and a graha rather than an element. Almost every placement rule on this site is that grid applied to one room: fire belongs in the fire corner, weight in the earth corner, water below ground in the water corner, and the centre stays empty.