In some Native American and New Age cultures, the medicine wheel is a metaphor for a variety of spiritual concepts. A medicine wheel may also be a stone monument that illustrates this metaphor.
Historically, the monuments were constructed by laying stones in a particular pattern on the ground oriented to the four directions. Most medicine wheels follow the basic pattern of having a center of stone, and surrounding that is an outer ring of stones with "spokes" (lines of rocks) radiating from the center to the cardinal directions (east, south, west, and north).
The alignment of the medicine wheel on the ground is placed in relation to the heavenly bodies and how they move through our lives.
The moon is represented by the west or the blackness of night. The moon helps to guide times of planting and is a way to record time and events.