foreach(dir
    Art
    Bamboo
    Bath
    Beach
    Blox
    Brick
    Cake
    Cave
    Castle
    Cheese
    Christmas
    City
    Compost
    CrazyMission
    Deepspace
    Desert
    EarthRise
    Eyes
    Freeway
    Fruit
    Golf
    Halloween
    Hell
    Hoggywood
    Island
    Jungle
    Nature
    Olympics
    Planes
    Sheep
    Snow
    Stage
    Underwater
    )
    add_subdirectory(${dir})
endforeach(dir)