EG: Analyzing Pli selon pli, I went to the Paul Sacher Foundation in Basle and studied your sketches. There were some astonishing findings. As an example, let us look at the vocal line in Improvisation I sur Mallarmé. I wanted to take a restricted material and investigate it, and I wanted to find out how this vocal line was generated. If we look at these music examples: First, here are the pitches of the vocal line, ‘Le vierge, le vivace et le bel aujourd'hu,’, etc. [Example 1, my notation, EG.]