supertux/data/images/background/misc/heatshimmer.surface

(supertux-surface
 (diffuse-texture
  (file "heatshimmer.png")
  (wrap "repeat")
  )

 (displacement-texture
  (file "heatshimmer-displacement.png")
  (wrap "repeat")
  (filter "linear")
  (animate 0 24)
  )
 )