#declare clouds = plane{
  -y, 0
  pigment{
    bozo
    color_map{
      [0 rgb .5]
      [.1 rgb 1 filter .2]
      [.5 rgbf 1]
    }
    turbulence .8
    scale 10
  }
  finish { ambient 1 }
}
#declare air = texture{
  pigment{ rgb <.2,.5,1> }
  finish{ ambient 1 }
}

plane{ -y, -30 texture{air} }
object{ clouds translate <0,29.9998,0> }

plane{ y, -1 pigment{ rgb 0.7*y } finish{ ambient 1 } }
camera{ rotate -15*x }