K

K for kaleidoscope
Well it's just kaleida actually.
Anyone who hasn't tried that built-in effect on aftereffects, go try it now.
I used a tiled square pattern from Photoshop which I applied the "Kaleida" effect on. Then it's just a matter of playing around with the settings to get different styles. Then I just matted it on to the animation. I think it's best applied to patterns.