command: povray -D +I{infile} +O{outfile}z.png +W{width} +H{height} +A && convert {outfile}z.png -swirl 80 {outfile}
template: |-
  global_settings { assumed_gamma 2.2 }
  
  #include "colors.inc"
  #include "textures.inc"
  #include "stones.inc"
  #include "finish.inc"
  #include "glass.inc"
  
  light_source {
      <-20, 50, 0>
      color White
  }
  
  camera {
      location <0, 15, -15>
      look_at <0, 5, 0>
  }
  
  plane { y, 0
      pigment {
          checker color White, color Black
          scale 4
      }
      finish {
          ambient 0.25
      }
  }
  
  sphere {
      <0, {{ t * 15.0 }}, 0>, {{ t * 15.0 }}

      material {
          texture {
              pigment { color rgbf <0.98, 1.0, 0.99, 0.75> }
              finish {
                  F_Glass4
                  ambient 0.25
              }
          }
          interior { I_Glass caustics 1 }
      }
  }