I just added a tutorial for the D11 Foldback Distortion from the early days of Reason. Check it out!
https://www.learnreason.com/index.php?threads/learn-the-d-11-foldback-distortion-in-reason.1273/
https://www.learnreason.com/index.php?threads/learn-the-d-11-foldback-distortion-in-reason.1273/