In the event you have a couple spare hours to burn off...:
If you didn't care for the prior Friday puzzle, then read NO further....
As long-time readers know I'm especially fond of self-referential or recursive conundrums in logic/mathematics, and in response to the "Futility Closet" puzzle from Friday Mr. Honner on Twitter linked to a far more elaborate such problem. It's TOOOO involved and complicated for one of my 'Friday Puzzles' but I link to it below for any who can't get enough of this stuff (not for the faint-of-heart though, nor the short-on-time! ;-)):