Conversation so far:
Where did Pierre Boulez begin his musical education in 1943?
In October 1943, he auditioned unsuccessfully for the advanced piano class at the Conservatoire, but he was admitted in January 1944 to the preparatory harmony class of Georges Dandelot.
What was Pierre Boulez's primary focus under Georges Dandelot?
preparatory harmony class

Question: Did he write any pieces during that time?
Self-contained rewrite: Did Pierre Boulez write any pieces during the time at the Conservatoire?