void mainImage(out vec4 o, vec2 u) {

vec3 c,p,r = iResolution;

float i, s, d;

for(; i++ < 1e2;
d += s = .01+ abs(1. - length(p.xy))*.3,
c += (1.3+cos(3.*p.z+vec3(6,4,2))) / s / d
)
for(p = vec3((u+u-r.xy)/r.y * d, d + iTime),
p.x *= .15,
p.z = .4*cos(p.z*.6),
s = 4.; s++ < 8.;
)
p.xz += asin(sin(p.zx*s))/s;;
o.rgb = tanh(c / 1e3);
}

https://www.shadertoy.com/view/tctfDs

#glsl #shader