Organic architecture, that is, natural architecture, may be varied in concept and form, but it is always faithful to principle. Organic architecture rejects rules imposed by individual preference or mere aesthetics in order to remain true to the nature of the site, the materials, the purpose of the structure, and the people who will ultimately use it. If this natural principle is upheld, then a bank cannot be built to look like a Greek temple. Form does not follow function; form is inseparable from function.