// create a rainbow arc
rainbow {
  angle 25 // degrees
  width 4 // degrees
  distance 1.0e7
  direction <0,-0.5,1>
  jitter 0.01
  arc_angle 180 // degrees
  falloff_angle 60 // degrees
// up <UP>
  colour_map {
    [0.000  color red 1.0 green 0.5 blue 1.0 filter 1.0]
    [0.100  color red 1.0 green 0.5 blue 1.0 filter 0.8]
    [0.214  color red 0.5 green 0.5 blue 1.0 filter 0.8]
    [0.328  color red 0.2 green 0.2 blue 1.0 filter 0.8]
    [0.442  color red 0.2 green 1.0 blue 1.0 filter 0.8]
    [0.556  color red 0.2 green 1.0 blue 0.2 filter 0.8]
    [0.670  color red 1.0 green 1.0 blue 0.2 filter 0.8]
    [0.784  color red 1.0 green 0.5 blue 0.2 filter 0.8]
    [0.900  color red 1.0 green 0.2 blue 0.2 filter 0.8]
  }
}