First and foremost kudos on coming up with one of the most unique testing mechanics I've seen in a TTRPG. Second, curse you for reminding me how long it's been since I was in school playing Paper Football.   The fact that you put instructions on how to create the ball is good, it's been too long. I really like the skill based mechanic that you have here, Its a generic framework for any setting, which is handy for quick pickup games.  The only thing I'm curious about is why the spread of the flips was 5, 3, 1, -1 ? That would seem to give very heavy weight to one skill in particular, as a player, I would try my best to favor that skill if at all possible to give myself more chances. But overall, as a generic quick pickup game system it seems fun.  Thanks for creating it!