The Oglala believe the circle to be sacred because the Great Spirit caused everything in nature to be round except stone. Stone is the implement of destruction. The sun and the sky, the earth and the moon are round like a shield, though the sky is deep like a bowl. Everything that breathes is round like the body of a man. Everything that grows from the ground is round like the stem d a tree. Since the Great Spirit has caused everything to be round mankind should look upon the circle as sacred for it is the symbol of all things in nature except stone. It is also the symbol of the circle that marks the edge of the world and therefore of the four winds that travel there. Consequently, it is also the symbol of a year. The day, the night, and the moon go in a circle above the sky. Therefore the circle is a symbol of these divisions of time and hence the symbol of all time.
For these reasons the Oglala make their tipis circular, their camp circle circular, and sit in a circle in all ceremonies. The circle is also the symbol of the tipi and of shelter. If one makes a circle for an ornament and it is not divided in any way, it should be understood as the symbol of the world and of time. If, however, the circle be filled with red, it is the symbol of the sun; if filled with blue, it is the symbol of the sky. If the circle is divided into four parts, it is the symbol of the four winds; if it is divided into more than four parts, it is the symbol of a vision of some kind. If a half circle is filled with red it represents a day; filled with black, the night; filled with yellow, a moon or month. On the other hand, if a half circle is filled with many colors, it symbolizes a rainbow.
One may paint or otherwise represent a circle on his tipi or his shield or his robe The mouth of a pipe should always be moved about in a circle before the pipe is formally smoked.