These pictures are from Klee's mature career. He painted them while he was teaching at the Bauhaus. During this time he was also a member of a group of artists called Die Blaue Vier (The Blue Four). The other three members were Wassily Kandinsky, Lyonel Feininger, and Alexej von Jawlensky. Like Klee, both Kandinsky and Feininger taught at the Bauhaus. The four artists lectured and exhibited together in Germany and the USA. 