That summer I went to the Aspen festival to be immersed in everything I could learn. Knowing only a bit of Mozart, I wasn't aware of the striking moment in Symphony No. 40 (the famous G minor symphony) when the last movement's main theme comes back as a loud unison tantrum, an atonal parody of itself. At 17, I didn't know about tone rows or atonality; it just sounded like crazy anarchy barely clinging to the rhythm and general contour of Mozart's theme.

It turns out this big surprise uses 11 different pitches in a row, every note except the tonic. A wonderfully wacky idea struck my adolescent mind to write some variations on that phrase, making it the original theme itself, rather than just a rogue variant in a development section. I didn't know how, but I was determined to anyway, and it only took 50 years and a yearlong quarantine for a solution.

The result is a two-part invention beginning with a development of the first half of Mozart's phrase, then developing the second half of Mozart's phrase, leading to a climactic coming-together of the complete 11-tone surprise, where Mozart's full "anti-statement" is revealed as the full statement of the Invention's theme.