Feudal dynasties in past dynasties all had strict patriarchal clan system, which included not only specific systems of food, clothing, housing and transportation, weddings, funerals and weddings, but also extremely strict and insurmountable equality system. In particular, the construction of private mansions is divided into royal family, princes, princes, quality officials and ordinary people. Moreover, the style, pedestal, steps, bay, roof, tiles, bucket arches, painting, and even the screen wall and gatehouse of the house have strict regulations. If people at a certain level violate this regulation, they will be accused of "ultra vires system" and the houses built will be confiscated. So at first, only six different kinds of wild animals were allowed to be placed on the king's roof. Old Beijingers describe a person who is so carried away that he doesn't know his last name. They often say that this man is a little "six beasts on the roof" and mock him for wanting to be king. Who knows that it has become the current "black chicken and six thin".