A Courtyard Dewlling in Beijing, China
Also ancient Chinese found out that the best living environment that produces a balanced Qi field is a rectangular environment, so standard classical Chinese constructions are all rectangular shapes. In fact, the Chinese have been living in rectangular constructions for thousands of years. One typical Chinese residential dwelling is the Courtyard Dwelling (Slideshow 1). It has a rectangular yard, and rectangular shaped rooms. Of course, there are some exceptions, such as Hall of Prayer (Slideshow 2) in Temple of Heaven in Beijing, China. This world famous hall is the only one round building in imperial constructions. It is a round building because it is a place the divine emperor worshipped and not for humans.
From the viewpoint of Qi, rectangular space has the most beneficial Qi field. That means the rectangular space is mostly suitable for us to live in.
According to Feng Shui, if a house lacks a corner, it may lead to ill fortune for the family member associated with that corner in the house.