float i,a,b,d;for(;i<1.;i+=1./(80.-cos(t/5.*PI)*48.)){d=fract(t/8.+i)*4.;b=floor(d);a=floor(b/2.);b=mod(b-a,2.);vec2 v=rotate2D(PI*fract(d))*vec2(.5-b,a-.5)*2.;d=FC.x/r.x-(a+b)*.5;b=FC.y/r.y-(1.+b-a)*.5;a=d*d+b*b;if(abs(d*v.y-b*v.x)<.01)o+=snoise3D(vec3(a))*i/a;}o.rg*=3.;o.r*=9.;