// CASSINI / Cassinian eggs '03.06
// By Tsutomu HIGO  E-mail: nj2t-hg@asahi-net.or.jp

#version 3.5;
global_settings {
  max_trace_level 4
  assumed_gamma 2.2
  }

camera {
  location <2, 30, -100>
  look_at <-0.25, -0.2, 0>
  angle 21.5
  }

light_source {<-50, 150, -75> color rgb <0.8, 0.8, 0.8>}

union {
  #declare N = 0; #while (N < 12)
    #switch (N)
      #case(0) #declare Pr = 0.0; #break
      #case(1) #declare Pr = 1.5; #break
      #case(2) #declare Pr = 2.5; #break
      #case(3) #declare Pr = 2.8; #break
      #case(4) #declare Pr = 2.9; #break
      #case(5) #declare Pr = 2.97; #break
      #case(6) #declare Pr = 3.00; #break
      #case(7) #declare Pr = 3.01; #break
      #case(8) #declare Pr = 3.03; #break
      #case(9) #declare Pr = 3.1; #break
      #case(10) #declare Pr = 3.8; #break
      #case(11) #declare Pr = 5.0; #break
    #end
    isosurface {
      function {pow(x*x+y*y+z*z+Pr*Pr,2)-4*Pr*Pr*x*x-pow(3,4)}
      threshold 0
      max_gradient 5000
      contained_by {box {<-8, -3, -8>, <8, 3, 8>}}
      //open
      translate x*(16-6*cos(pi/24*N))
      rotate z*(-360/12*(N+1)-7*N+0.66*N*N)
      no_shadow
      }
  #declare N = N+1; #end
  texture {
    pigment {color rgb <1, 0.95, 0.85>}
    finish {
      ambient 0.4
      diffuse 1
      reflection 0
      specular 0.1
      phong 0
      brilliance 1
      }
    }
  translate <-3, -2.3, 0>
  }

background {color rgb <0, 0.2, 0.7>}