[danwills]

Ah silly me, you put the sources in the comment!! Thanks for that I will have a read for sure!

It struck me as looking a bit like a demoscene plasma effect but with a radial/angular aspect! (also reminds me of cymatics diagrams a bit!)

I experimented with non-integer symmetries and it seemed not to introduce discontinuities, and I made it produce an RGB value for fun too:

https://www.shadertoy.com/view/7XsGWs

[danwills]

Wow this is too much fun for simple sum-of-cosines but I shouldn't be surprised (have played with FFT a bit, and I know of Reimann Zeta Function.. sines are amazing!)

I doubled the angle so that it doesn't drift to the side any more.. and put it back to 7-symmetry, but left it with the coloring I added (now adjustable via consts):

https://www.shadertoy.com/view/7Xl3Ws

And a small tweak:

https://www.shadertoy.com/view/73lGDs

If you squint with it on fullscreen on that last one there's a wonderful mixture of things feeling like they are rotating vs flowing inward-and-outward from 'centers' (like it's ambiguous whether it's curl or divergence somehow for my eyes/brain at least!).

Hooray for sines and cosines and shaders and thanks for motivating me to play!

[airstrike]

So cool! It reminds me of the kaleidoscope I played with as a kid. Truly mesmerizing.

FYI your second link is not working

[danwills]

Ah thanks for letting me know! I had not set it to public. It's public now though! Glad you enjoyed it!