Negative harmony MIDI effect
After watching this very interesting interview with Jacob Collier about music theory: https://www.youtube.com/watch?v=DnBr070vcNE&t=361s
I found it very interesting to develop a little algorithm which could perform this "negative harmony" transformation to a stream of MIDI data by defining a reflection axis.
Here you will find a more detailed explanation about the concept:
Try it on your MIDI compositions... really refreshing results with minimal effort...