Looks really cool, these look like so much fun I want to try this out too!! I like how each is a different color. Is the idea to tell a sort of story with each picture?
It's super easy - just use the default photoshop hard brush on 100% opacity and just stick to three colours. Build it up from the background colour to the foreground and then go crazy. And yeah, sort of, we had to write continuously about one word for thirty seconds and then art it up. Thank you!