That is know as the lee side
side of a building called
There is no building called The PolygonBuilding.The US Department of Defense is headquartered in The Pentagon Building.
I'd call it a triangular building but the answer you are looking for is pyramid but that is NOT what a triangular building is called.
The longest side of a triangle is called the Hypotenuse.
The building is 77 feet (23 m) tall, and each of the five sides of the building is 921 feet (281 m) long.
A porch is a sheltered area that stands out at the front, rear or side of a building.
The lee side
The area on the dry sheltered side of a mountain that receives very little rain is called a "Rain Shadow"
side of a building called
The lee side is the sheltered side, the side of something away from the wind.
A sheltered port is a harbor.
The side sheltered from the wind.
The leeward or lee side.
A porch is a sheltered area that stands out at the front of a building.
Lee means the sheltered side. In the lee of the stone would mean the side of the stone untouched or sheltered from wind, rein or anything really. in the lee of anything just means the sheltered side of that particular thing.
The leeward side is the downwind side, the sheltered side
Lea