Conversation so far:
What was a famous work that came out during the Mystical-abstract period?
Fohn im Marc'schen Garten (Foehn at Marc's Garden) was made after the Turin trip.
What other painters were famous during this period?
in the fashion of Paul Cezanne and Robert Delaunays' cubistic form concepts.
Was World War I important in the Mystical-abstract period?
Under the impression of his military service he created the painting Trauerblumen (Velvetbells) in 1917.

Question: Who were Klee's colleagues during this period?
Self-contained rewrite: Who were Klee's colleagues during the Mystical-abstract period?