Siheyuan, as its name implies, is surrounded by houses and has a yard in the middle. Generally, one family has one yard. Of course, there may or may not be. Maybe a poor family is just a big yard for several families, but it is not a big yard.
In fact, influenced by the traditional culture of China, quadrangles have some concepts of respect and inferiority, because the houses in quadrangles have four directions, southeast and northwest, because the ancients have concepts of respect and inferiority. Moreover, quadrangles are not only places to live, but also contain profound traditional culture. The architectural features of quadrangles are very particular about geomantic omen.
Architecture pays great attention to geomantic omen, some respect and inferiority, and now it also pays attention to the old and the young. This is the theory of Yin and Yang that we have had since ancient times. Ancient people always looked at feng shui when building houses. Geomantic omen theory, I think it should be an ancient building in China. So, according to Feng Shui, we seem to have decided who lives in the southeast and northwest of the quadrangle.
Moreover, quadrangles vary in size and style. For example, the smallest quadrangle enters the courtyard, and the second one enters the courtyard. It seems that the larger quadrangles are generally large families with many rules.
Although the quadrangles are slightly different, the overall architectural features are all four courtyards. It is more programmed and easier to build, and the format of the house is similar, which is the difference between simplification and complexity.