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.;
    p.z-=6.;
    p.zx*=rotate2D(t);
    p.yx*=rotate2D(t);
    for(j=0.;j++<4.;)
        p=abs(abs(p)*rotate3D(i/j+t,vec3(-1))),
        d=max(dot(p.zy,p.xz),dot(p.yx,p.xz))/d,
        d-=dot(p,p)/1e4;
    e+=d;
}o+=vec4(exp(p/e/d),1)*3./i;