Many protagonists of early 20th century architecture explored the possibilities of the construction kit and developed their own versions. Their construction kits are images of building. The pragmatic goals, be they in the toy or construction industry or even in the design of stage sets, were usually not achieved. Rather, they reflect the way of thinking and design practice of the respective architectural concept.Three examples of early modernism are examined: Together, the building sets of Bruno Taut, Walter Gropius and Wilhelm Kreis show different relationships to materiality in architectural design: the glass building was to become a literal reality for Bruno Taut; the fabricless "Raumkörper" allowed Walter Gropius to experiment with novel building compositions; and the massive stone building was an archaic myth for Wilhelm Kreis.