Hi Ashley,
this is Android, I just joined this forum and noticed you question,
for the effect in this video I have particle view open on my main screen, then I use a program called cam twist, its free to download for mac, https://camtwiststudio.com
cam twist allows me to select the particle view window and send it to my second monitor, or in this case the projector, in cam twist I can add effects like the mirror or kaleidoscope effects.
camtwist is very light weight and you can control the output resolution and frame rate to reduce any lag,
the particles are also controlled with a wacom tablet,
hope that answers your question
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