F² = Prototypes, Mockups and Samples ''w 52 designsolutions I spring 2022 orks great in planning; not so great in practice. " This frequently heard statement says a lot about the value of prototypes and mock-ups. If only we could visit the completed project in the future to evaluate the form and function of the custom woodwork design. F² = Form follows Function. Does it look the way it was imagined, designed and specified? Does it perform as well as imagined? Product users tend to fall out of love with something that doesn't correctly perform no matter how good it looks.