#version 3.7;

// runtime: 4.5 minutes
camera{
	location <-2.5, 5, -5>
	look_at <-0.2, 0.0, 0>
	angle 29.21
}

light_source { <-15,  5, -20>, rgb<0.7, 0.5, 0.2> }
light_source { < +5, 10, -5>, rgb<0.5, 0.6, 0.9>  }

#declare f=function(i,x,y,z,xc,yc,zc)
	{
		select(i>0 & x*x+y*y+z*z<4, 0,
			sqrt(x*x+y*y+z*z),
			f(i-1,(x*x-y*y)*(1-z*z/(x*x+y*y))+xc,2*x*y*(1-z*z/(x*x+y*y))+yc,-2*z*sqrt(x*x+y*y)+zc,xc,yc,zc)
		)
	};

isosurface{
	function{f(13,x,y,z,x,y,z)}
	threshold 2
//	max_gradient 9200
	evaluate 16, 1.29, 0.7
//	max_gradient 8252
	contained_by{
		sphere{<-0.5,0,0>,2}
	}
	
	pigment{ color rgb<1, 0.6, 0.8> }
	finish { phong 0.5 }
}