A weird effect I created by attempting to plug the last the equation from THIS VIDEO:
https://www.youtube.com/watch?v=p2c0-42XpJQ
I had to make a workaround to prevent the square-root-of-zero bug from making PICO-8 freeze.
DISCLAIMER: I have little or no understanding of the math behind this, I just threw it together and chanced upon a cool swirly pattern. Yay me.