float i,e,R,s,x,y,z;vec3 a,q,p,d=.5-FC.rgb/r.y;for(q.yz--,a=q;i++<1e2;i>76.?e+=1e-4,d=a:d){e*=R;p=q+=d*e*.5;o+=log(++e+cos(z/6.+vec4(0,1,2,0))*.3)/1e2;p=vec3(log(R=length(p))-t*.5,e=-p.z/R,atan(p.x,p.y));for(z=s=1.;s<1e2;s+=s)e+=exp(x=sin(y=PI*(dot(cos(p*s),p/p)))-1.4)/s,z+=x/y;}