Particle Showers?

[THMG]

I'm working on an ice-themed mapset, and wanted to use the white particle fountain to shower white particles down to mark an area that will cause cold damage when the player enters, but the pitch and roll functions don't seem to change the actual angle the particles are projected, so I was wondering:

How do you change the angle which the ZDoom particle fountains eject particles?

[scifista42]

You can't do that with fountains, but you can if you spawn the particles via ACS: https://zdoom.org/wiki/SpawnParticle