make the rubber band a "flat" surface so bounce is a bit more predictable. This is mostly just for testing. It looks a bit odd walking on it, and unpredictable bounce might even be just fine...

foreach(dir "Fonts" "Forts" "Graphics" "Locale" "Maps" "Music" "Sounds" "Themes" "Missions" "Names" "misc" "Scripts")
  add_subdirectory(${dir})
endforeach(dir)