The Mentawai hang skulls of domesticated animals facing away from their house, and hang skulls of wild anamals facing toward the house.  (I could have that backwards!)  Anyway, there is some logic involved that keeps bad spirits away from the house and good ones within.  Notice the use of plastic twine as well as traditional.  I held the flash on this one.

Photo by Me (Canon EOS 630 50mm f 1.8)