The whole universe is made of five elements and the elements have a way of settling under universal principle whether it is an atom or a galaxy. As depicted in the above diagram, water element naturally gravitates towards NE, fire towards SE, earth to SW and air to NW. Space element is a sheer absence of other four elements and is the most mysteriously obscure amongst the five elements.

When you cut a magnet, it becomes another holistic magnet. Similarly, when a piece of land is separated by natural or man-made boundaries, this piece of land acts as a separate entity with energies realigning within. The whole concepts of vāstu śāstra (Science of Architecture) is based on this fact.

Hence, in the countries with longer established civilization, like India, China and Greece each lot has a prominent brick or rock fence and within the boundaries, special care is taken to ensure the elements are settled, stable and at ease. Even the sacred places, that are build under the principles of Āgama śāstra, shares the same basic principle.

Living Being influenced by the forces of nature 

Apart from the settlement of the elements, these lots or the buildings are constantly polished with beneficial energies and also affected by the malefic energies. The magnetic energies of the north and the solar energies of the east (ultraviolet rays) exert positive, life-supportive influences, while the south (infrared rays) and the west (gamma rays) exert influences that are not life-supporting. Hence in established civilizations, buildings were designed to receive the abundant, life-enhancing energies from the north and east, while shielding their inhabitants from the gamma and infrared rays of the west and south. The positive energies from north and east should flow around the structure without obstruction and collected in the southwest area of the building, where they support the health and well-being of the inhabitants.

Four important corners and their significance:

North East (Water): This corner needs to be open, unobstructed, least heavy in the whole lot. Hence it is beneficial to have a street emerging in this corner, not having tall trees and digging the ground for well, pool, etc. The common side-effects of not adhering to these principles is that, it draws the water element from the bodies of the inhabitants. As as result, they will suffer lack of attention, unable to recall from memory faster, won't be able to accumulate knowledge easily. If you try not drinking water for a day, you'll realize all these symptoms experientially.

Since humans are made of 72% water, this corner is given most significance in vāstu śāstra. Hence, inside a lot, have more vacant space in this corner and inside a building ensure this is the mostly vacant room, like a living room.

South East (Fire): This corner demands heat. It is ideal to have a fire pit, centralized heaters, geysers, stoves, etc. Hence it is also ideal for kitchen, if it is being used often. In the whole lot, this corner needs to be relatively hotter. Or else, it'll start pulling the heat from its occupants. Once your body heat is obstructed, it immediately impacts the digestion and triggers a domino effect on the health of the inhabitants. Simple things like keeping this corner red and lighting an ever-lasting lamp will fulfill the needs of this SE corner.

South West (Earth): SW corner needs to be heaviest and well blocked in the whole lot or the building. The earth dug out of NE to make that lighter, can be dumped here to make SW heavier. The earth element in our bodies gives the stability and resistance to environmental changes. If this corner, by any means is not fulfilled with its demand for earth, it starts pulling the earth element from the occupants. This makes the occupants undergo huge swings from weight, wealth, moods to relationships.

Earth being second most largest ingredient in humans, this is an important corner next to NE. To quench its needs for earth, SW is apt for heavy and obstructing, like tall and thick foliage trees, gym, taller walls, rock dumps, etc. A hill on SW is a natural boon. When you take USA as a lot, SW beaches are the most rockiest with natural hilly landscape.

North West (Air): Air element gravitates towards this corner. Making this a perfect corner for septic and restrooms. When the air demand of NW is not met, the occupants contribute their air and it impacts their psyche. Air is the insulation between the neurons in the brain. When this insulation is impacted, possible short-circuits results in unexpected psychological outcome.

Other Four directions and their significance:

Every individual is equipped with different levels of attributes like courage, righteousness, intelligence, etc. Their astrological birth charts are the indicators of those. Their dwellings will often be in alignment with it. The influence of the dwelling units on such attributes cannot exceed the max and cannot go below the minimum allocated to the individual. vāstu śāstra thrives to provide the max possible so as the inhabitant gets the most out of their life.

North (Air and Water): Good psyche and knowledge results in good Intelligence. Hence this region is responsible for the intelligence of occupants.

East (Water and Fire): Sun raises at east. Solar energy is absolutely essential for any form of life on earth. Where it is available automatically, it is taken for granted. Apart from this, there are other influences sun exerts on humans. To name few, the level of confidence and righteousness are dictated by sun.

South (Fire and Earth): This region dictates the courage and initiative of the occupants. When you see a normally courageous person move into a new home and acts cowardice, you can confidently say that the south end of the home does not comply with vāstu śāstra.

West (Earth and Air): A stable west with earth in south and air in north denotes greater levels of patience and discipline in the occupants.

These is the foundation on which the whole vāstu śāstra is built on and by no means what i've mentioned consolidates the depth of vāstu śāstra. This is a deep science that has been fading away from practice due to several fraudulent individuals trying to profit from the misery of unsuspecting victims. Understanding the basic science behind it and ensuring these general principles are met in you dwelling place, weather it be home or work place or a temple is ample enough to get the most out of this life.

More you learn about it, more you can hone your knowledge, but beware, all these anicient śāstras are bottomless abyss. If you embark on a journey to find the bottom, you'll be absolutely lost and become an annoyance to the people around you. So always keep a checkpoint on when and where to stop the research, implement and move on.