At his GDC keynote today, Nintendo president Satoru Iwata walked through designer Shigeru Miyamoto's design process. Miyamoto doesn't write design documents. He shares his ideas with a small group of developers who then make a prototype. Iwata said the developers may spend as many as two years making prototypes. He showed this example: the prototype for "Wii Sports" boxing. Good prototypes get greenlit for production. Iwata siad he tries to avoid asking Miyamoto how things are going, so as to keep the development team from cutting corners.