-Black Disc-
when picking up the disc off of the shelf by WW build-able, wait for rap round and place disc on gramophone in broken building, left of spawn. I shot it with PAPd WW but you can jut interact with it i believe

-Middle Fountain-
It seems to be some kind of chance or lottery mechanic when throwing grenades in the fountain. you will either gain 200 points or lose 150. When gaining 200, the water will rise. When losing 150 points, the water lowers. If you gain 200 points multiple times in a row, the water will rise all the way up and begin to boil. Idk what happens when you lose multiple times in a row though.