Our #dmgBoost challenge is back to a random playable item.
"The Hidden Object Rite" by #ChristopherHobbs:
http://musicgames.wikidot.com/sub:scratch-015
It's from #ScratchOrchestra's #NatureStudyNotes (1969), digitised for the #wiki from handwritten copies as it was originally published.
It has guessing, but rules don't determine the music a lot, only the overall length of improvisation and the moment when some of the players should stop.
The cooperative approach would make playing suggestive ("musical hints").