Moiré, that is. The type of pattern that looks like it is moving thanks to how it overlaps on itself!
I figured out how Moiré brushes worked and what would make them work best for me. Here's what I came up with.
The brushes:


Each brush is very customizable. I encourage you to turn different features on & off, and see what works best for you. They're great for experimental and psychedelic art.
There's also a couple of patters you can use:

Along with a brush that is good for color changing, the overlay brush:

Here's the art I used to test 'em out. All drawn & painted with the brushes of this set!

Drawing & Painting
Pattern