Conversation so far:
What was one of Paul Klee's significant works during his mature career?
Paul Klee's Ad Parnassum (1932) is considered his masterpiece and the best example of his pointillist style.
What is something significant about Paul Klee's Ad Parnassum?
Ad Parnassum is one of Paul Klee's largest, most finely worked paintings.

Question: What are some other works from his mature period?
Self-contained rewrite: What are some other works from Paul Klee's mature period, besides Ad Parnassum?