3 Royalty-Free Audio Tracks for "Retrograde"

Beethoven's retrograde version of his fugue subject (Hammerklavier Sonata)

Hammerklavier fugue subject, retrograde version, last four bars

I have been working on my twelve-tone program (in chuck). 1 - random 12 tones with random note-length for prime. 2 - then retorograde is played. 3 - after that prime and retrograde at the same time (3 times). Here the note-length is a average value.