form is function
It's said that the Finnish architect Alvar Aalto designed a concert hall foyer in such a way that people when walking across the foyer towards the concert hall would not have to interrupt the conversations they were involved in. They would not need to find and interpret signs or difficult room forms in order to find their way. Aalto put a light shaft at the end of the foyer. People walked towards the light and having done that found themselves just above the stairs to the concert hall. [Ejhed, personal communication]So one function of the foyer is that it does not interrupt ongoing conversations. This function is not visible in itself but it depends on the real, visible forms. Form as function. What is interesting in this example is that the environment supports human behaviour. We can act without paying that much attention to what we do.
function design sign user semiotic product semantics web functional analysis industrial design