You have noticed that everything as Indian does is in a circle, and that is because the Power of the World always works in circles, and everything tries to be round..... 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, for theirs is the same religion as ours....
Even the seasons form a great circle in their changing, and always come back again to where they were. The life of a man is a circle from childhood to childhood, and so it is in everything where power moves.
Source: Visions of the Buffalo People -Linda Little Wolf Page 109