I did my 6 May 2020 improv weekly using only the white keys, and for a while I've been pondering doing one with only black keys as well, but I've always felt that it would be far too restrictive. Someone suggested maybe compromising and allowing white keys in the left hand, but only black keys in the right hand. Well... this is the result :)

I've done several special challenges in these improv weeklies - no black keys, no pedal, weird time signatures... but this one was definitely the hardest so far. Quite a few takes were ruined by accidentally pressing a white key with the right hand several minutes in, and it took all my concentration to see this one through to the end. Hope it was worth it.