Everything the Power of the World does is done in a circle. The sky is round, and I have heard that the earth is round like a ball, and so are all the stars. The wind, in its greatest power whirls. Birds make their nest in circles... The sun comes forth and goes down again in a circle. The moon does the same and both are round. Even the seasons form a great circle in their changing, and always come back again to where they were.
"Black Elk Speaks : being the life story of a holy man of the Ogalala Sioux" by John Neihardt, (Ch. 17), 1961.