What makes a new idea a good idea? How do constraints motivate novel thinking? What is the role of one's culture and environment in cultivating new ideas? What makes a mathematical proof elegant? In this session, we shall explore creativity, specifically in the context of musical composition and mathematical proof with progressive rock drummer Bill Bruford (Yes, King Crimson, Earthworks) and mathematician Günter M. Ziegler (Free University of Berlin). There will be an open Q&A period at the end.