// Entry code: qcdavh
// Name      : Mikihiko Nishiara
// Frame rate: 6
#declare r = 2 * pi * clock;
#declare h = r + sin(r) / 2;
#declare camera_location =
  <-5 * sin(h), 1 + 1.4 * cos(h), -4.25 - 4 * cos(h)>;

camera {
  location camera_location
  look_at 0
}

light_source {
  <-2.5, 8, -6>
  color rgb <8, 9, 8> * 9
  fade_distance 1
  fade_power 2
}

light_source {
  camera_location
  color rgb <8, 8, 9> * .1
  fade_distance 1
  fade_power 2
}

#macro menger(pos, S)
  #if(vlength(pos - camera_location) < S * 30)
    #local s = S / 3;
    #local i = 0;
    #while(i < 27)
      #local X = mod(i, 3) - 1;
      #local Y = mod(div(i, 3), 3) - 1;
      #local Z = mod(div(i, 9), 3) - 1;
      #if((X = 0) + (Y = 0) + (Z = 0) < 2)
        menger(pos + <X, Y, Z> * s, s)
      #end
      #local i = i + 1;
    #end
  #else
    box{
      -.5, .5
      pigment {
        color rgb 1
      }
      scale S
      translate pos
    }
  #end
#end

menger(0, 3)