The use of certain colors, numbers and the cardinal directions in traditional Chinese architecture reflected the belief in a type of immanence, where the nature of a thing could be wholly contained in its own form. Although the Western tradition gradually developed a body of architectural literature, little was written on the subject in China, and the earliest text, the Kaogongji, was never disputed. However, ideas about cosmic harmony and the order of the city were usually interpreted at their most basic level, so a reproduction of the "ideal" city never existed.