In 1963, the Lehni company, which does sheet metal work for construction projects, began to produce metal furniture as well. The owner, Rolf Lehni (1927–1981) taught at the Kunstgewerbeschule Zürich (today ZHdK), and helped students to build their prototypes in his workshop. One of them was Andreas Christen (1936–2006), who studied under Willy Guhl and then opened his own design studio in 1960, making a name for himself internationally as a visual artist and product designer. Christen was a minimalist who geared his designs to the American standard of rational series production. He began experimenting early on with plastic and aluminum, which were not yet in widespread use for domestic interiors. His aluminum shelving, which he first designed for his own use, was chosen by Max Bill for the interior of the pavilion of the Swiss Book Dealers’ Association at Expo 64. Aluminum panels, stabilized by bending and punching, are used here for both the frame and the shelves, and are reinforced by diagonal bracing. Christen continually revised the Lehni shelf, adapting it to new requirements. At first it was sold almost exclusively in white, but later it was also available spray-painted in bold blue and red, while today the colorless anodized version is the most popular.