This foam was made by a very warped perlin, and further warped by a displacement to scaler function from the island itself, but that was no good. I was trying to get the foam sort of following the outlines of the stones, but the warping by those stones is hard and perpendicular somehow. Doesn't really work. I will try what distort by normal can do, but that needs displacement first. Maybe a mask can be made out of that, have to experiment.
I'm now doing a version with a voronoi blue node base.