Form really does follow function when I design signs. It sounds obvious, but information is critical on a sign; readers need to know how to get to their destination. Whatever style I employ, it must not interfere with the information but must serve it. I have to consider how all of the variables will interact; will the materials that I am using reflect light? Will the colors contrast with the walls or with the sky? Will the letters and numbers fade into the background? At what distance can the information be read? Do I need to use icons rather than language?