float j,i,e,v,u,S;vec3 w,p,q;for(q.yz+=.6;p=q+=(FC.rgb/r.y-.5)*e,e=v=3.,p.xz*=rotate2D(t),w=p/e,i++<1e2;e=min(e,(w.x+w.z)/S),o+=.01/exp(e*S))for(j=S=.7;j++<9.;e=min(e,max(length(p.xz=abs(p.xz)-.4),p.y=2.-p.y)/v))w.y-=2.5,S/=u=min(dot(w,w),.5)+.02,w=abs(w)/u-.4,v/=u=dot(p,p),p/=u;