ABSTRACT
In this chapter, the authors show some prototypical examples of mock-ups. Their examples range from "cardboard computers" to "computer mock-ups" hinting at the pros and cons of less and more advanced artifacts for envisionment of future use. In summary, mock-ups become useful when they make sense to the participants in a specific design language game, not because they mirror "real things," but because of the interaction and reflection they support. The authors discuss some of the possibilities in the borderland between the "cardboard computers" and the "real" prototypes. Before they turn their attention to the use of computers in mock-ups, they briefly outline some advantages and shortcomings of simpler materials to get a better understanding of what might be gained or lost from the use of computers.
