Triangle

A triangle gives the feeling of stability. Roof tops are often constucted in a triangle shape. We can think of practical reasons for building this way . Generally, rain and snow does not stay on a roof with a pitched roof.  

From a physics stand point, a triangle is stronger than other shapes.  Unlike rectangles, the angle between any of the triangle's two sides can not be changed without changing the length of one of its sides. A triangle is also the most stable, in that the triangle has a large base and a low center of gravity.

Many buildings resemble the triangle, find images of a Pyramid and the CN Tower. Look around your neighborhood, can you see buildings with triangle shapes?