Deltographos::Blog

float i,j,d=.1,e; vec3 p;
for(i=0.;i++<64.&&d>1e-4;){
    p=vec3((FC.xy-.5*r)/r.y,1)*4.;
    for(j=0.;j++<2.;)
        p=abs(p/i/d)*rotate3D(t*.5,vec3(-p.z,p.y,p.z)),
        d=max(length(atan(p.zx)),length(tan(p.yz)))/d,
        d-=dot(cos(p),1./sin(p))/d;
    e+=d;
}o+=vec4(exp(p),1)*3./i;