global_settings{max_trace_level 99}#macro M(C,N)sphere{0 1pigment{rgbt 1}interior{media{density{julia I N scale.5color_map{[0rgb 0][.4rgb C][1+C.x/3rgb.3-C]}}emission.5}}hollow translate.1/N+z*2}#end#local I=0;#while(I<1)M(<I,0,1-I>,I*30)#local I=I+.1;#end