The buffalo skin tipi was the dwelling most commonly used by the nomadic
Indians of the western plains.  The skins were sewn together with buckskin
thongs.  The door of the tipi was a flap, also made of skin, which could
be closed with wooden pegs.  The tipi was a sophisticated dwelling that
could adapt to a variety of environments.  During the harsh winters on the
plains, the top ventilators could be sealed up to keep out the could and
the wind.  In the summer, the poles could be shifted to catch a breeze
and the bottom of the skin covering raised to cool the interior.