PRIMITIVE ART 19 
probably an outgrowth of the embroidery in porcupine-quills 
which was characteristic of the Indians before they came in 
contact with the whites. The forms which are the constituent 
elements of decorative motives are very simple and characteristic. 
They consist throughout of regularly arranged 
triangles and rectangles, mostly in brilliant and 
strongly contrasting colors, and often also show- 
ing sections of varying color. Sometimes the 
decoration is applied to the whole surface, 
sometimes only a particular part of the object 
is decorated. Much of the painting is done on 
rawhide, but most of the embroidery is made 
on soft skin. The background of the painting 
is usually rawhide, while the beaded designs are 
often set off against a background of white or colored beads. 
The manner of combination of triangles and rectangles is 
so peculiar, that decorated objects obtained from the Plains 
Indians can readily be distinguished from objects from any other 
part of the world. Although there is a certain sameness among 
all of them, each tribe has certain peculiarities of its own. The 
most characteristic form, which occurs over and over again 
in Indian decorative art, is the somewhat pointed triangle, 
either divided into halves of different color, or including an- 
other triangle of different color. 
This form is generally explained as 
the tepee, the tent of the Plains 
Indians. Another form which is 
almost as frequent is a very obtuse 
triangle, often with a small rec- 
tangle in the middle. This is in- 
terpreted as a hill, while the center 
figure is often called a cave in the 
hill. We find also very often de- 
signs consisting of parallel lines, 
sometimes broken up by equidistant short patterns of different 
color. These lines are generally interpreted as trails; and breaks 
in the lines, as camping-sites or other interruptions of the con- 
tinuous trail. 
