Hi all, this is a piece by Yute Sato (if I am not mistaken). I am curious how this very specific gradient was made, it seems like it was a Ctrl-D duplication on some gradient (mesh?) on Illustrator. Though as you can see, on the bottom half some of these looked dragged and painted over, with the gradient duplicated and static. I think this is an interesting result and was wondering about how to approach it!
I think it's less complicated than you think.
Just make some gradient. Here I've made a quick copy of the gradient used in your example.
Then use that same gradient for a bunch of fills and/or brush strokes. Maybe use Blend Tool to make some of those repeated patterns. Maybe rotate the gradient in some of the shapes like in the example.
This was made without much effort. To make something great it of course requires more work.