The developments at the Bauhaus are represented by design classics by Marcel Breuer, such as his 1922 slatted chair, a constructivist sculpture, or his functional tubular steel furniture of 1926. In Weimar a total of thirty-one apprentices and three guests studied in the carpentry workshop in four years, including Erich Brendel, Marcel Breuer, Erich Consemüller, Erich Dieckmann, Hans Fricke and Felix Klee. At the Bauhaus in Dessau there were Franz Ehrlich, Ernst Gebhardt, Hans Georg Groß, Heinz Tetzner and Peer Bücking. The number of students rose from an average of eleven in Weimar to a maximum of twenty-two at the Bauhaus in Dessau in 1928. From 1925 Marcel Breuer developed his tubular steel furniture. Breuer used the development of precision steel tubes for the chemical industry in furniture building. Mart Stam's cantilever chair, a chair without back legs that made full use of its steel tubing’s spring quality, was immediately adapted by Mies van der Rohe and Breuer.