#declare CLOCK = clock;
//#declare CLOCK            = 1;
#declare BEARING          = int(CLOCK / 8) * 45;
#declare ELEVATION        = mod(CLOCK,  8) * 45;
#declare RADIUS           = 2;
#declare N_VERTEX         = 16;

plane { <0,1,0> 0 pigment { rgb<1,1,1> } translate<0,-4,0> }
/*
plane { <0,1,0> 0 pigment { checker <0.8,0.8,0.8> rgb<1,1,1> }
translate<0,-2,0> }
union { /// axes
 cone { <-1,0,0> 0.5 <1,0,0> 0.1 pigment { rgb <1,0,0> } }
 cone { <0,-1,0> 0.5 <0,1,0> 0.1 pigment { rgb <0,1,0> } }
 cone { <0,0,-1> 0.5 <0,0,1> 0.1 pigment { rgb <0,0,1> } }
 scale 2
}
*/
#declare HALF_SEPARATIONS = array[2]{0  , RADIUS / sqrt(2)};
#declare CENTROID_X       = array[2]{4, -2};

#local I = 0;
#while (I < 2)

 #local HALF_SEPARATION = HALF_SEPARATIONS[I];
 #if (HALF_SEPARATION = 0)
  #local ANGLE_MAX = pi / 2;
  #local PEAK_X    = 0;
 #else
  #local ANGLE_MAX = acos(-RADIUS / (RADIUS + 2 * HALF_SEPARATION));
  #local PEAK_X    = RADIUS * RADIUS / (RADIUS + 2 * HALF_SEPARATION)
- HALF_SEPARATION;
 #end

 #local EIGHTH =
 union {
  #local T = 0;
  #while (T < N_VERTEX)
   #local T = T + 1;
   #local ANGLE_T   =  T      / N_VERTEX * ANGLE_MAX;
   #local ANGLE_T_1 = (T - 1) / N_VERTEX * ANGLE_MAX;
   triangle {
    < HALF_SEPARATION + RADIUS * cos(ANGLE_T  ), 0, RADIUS * sin(ANGLE_T  )>,
    < HALF_SEPARATION + RADIUS * cos(ANGLE_T_1), 0, RADIUS * sin(ANGLE_T_1)>,
    < PEAK_X, RADIUS * sin(ANGLE_MAX), 0>
    #if (mod(T / N_VERTEX * 8, 3) > 1)
     pigment { rgb<0.9,0.7,0.5> }
    #else
     pigment { rgb<0.7,0.6,0.5> }
    #end
   }
  #end
 }

 #local HALF =
 union {
  object { EIGHTH }
  object { EIGHTH scale<1, 1,-1> }
  object { EIGHTH scale<1,-1, 1> }
  object { EIGHTH scale<1,-1,-1> }
 }

 union {
  object { HALF }
  object { HALF scale<-1,1,1> rotate<90,0,0> }
  rotate    <0        ,BEARING,0            >
  rotate    <0,0      ,ELEVATION            >
  translate <0        ,0      ,CENTROID_X[I]>
 }

 #local I = I + 1;
#end

camera {
 right     x * image_width / image_height
 location  <20,0,0>
 look_at   <0,0,0>
 angle     30 * image_width / image_height
}

union {
 light_source {
  <10,10,0> color 0.5
  area_light <0,3,0>, <0,0,1>, 3, 3
  adaptive 1 circular
 }
}
global_settings { ambient_light rgb <9,9,9> }
background { color rgb <0.9,0.9,0.9> }