What does the form follow?

"Form obeys function" is a famous saying of louis sullivan, a modernist architect of Chicago School. His original words should be "Form obeys function, which is a law". In the history of design, the problem of form and function is a topic that is constantly discussed and revised. Sullivan's sentence is the earliest classic statement on this topic, which has a far-reaching influence. Bauhaus's functionalism theory only pushes function to a higher level. They even think that good function is the form of beauty, and there is no need to discuss form further. The more classic famous sayings, the easier it is to become the focus of discussion. For example, in the history of design, Mises's "less is more" was changed to "less is boring" by robert venturi, a pioneer of post-modernism theory. Therefore, Sullivan's famous saying is naturally doomed. Form follows art; Form follows finance; Form follows profit; Form follows the environment, but the most influential is the famous German design company-Frog Company. Frog's design concept is "form follows passion", which embodies the relaxed and humorous characteristics of postmodernism. In the field of architecture, Charles Correa, a famous Indian architect, put forward that "in India, the concept of architecture must not be determined only by structure and function, but also by respect for climate", which further condensed the design methodology of "form follows climate" and provided creative ideas for urban design combined with specific climate, thus giving the city a strong regional color.