If one lookes at the collection of protein structures in the Brookhaven Protein Structure Database, one is reminded of the works of an Oregami artist: Certain basic folding patterns are used over and over again and clevely modified by minor adaptations to generate a wide variety of different protein structures. Where one such folding units is insufficent to generate the required complexity, multiple domains can be combined, such as in the camel or giraffe structure on this picture or the immunoglobulin molecule shown on the next slide.