This little improv simply wouldn't have been possible a few months ago. It's a single pass, with just one synth patch, using both hands and one foot!
One of Yoshimi's little band of helpers (TM) wrote the code that enables me to MIDI-learn almost every possibly control in real time, and I used this to considerably change the timbre while playing. I hope you will enjoy:
Improv Zen
I've attached both ogg and mp3 files.