Ouroboros is a symbol used in ancient cultures around the world. It consists of a snake biting its own tail, forming a circle, and like other circular motifs, it can symbolize unity or the cyclical nature of many aspects of life. Though the symbol of Ouroboros is widespread, its meaning is not universal. Sometimes, it is meant to symbolize the joining of opposites, similar to the yin-yang; suggestive that opposites not only coexist but are also related in a cyclical manner. In this context, it is sometimes depicted as half light and half dark. Ouroboros may be a symbol of eternity, infinity, unity and even resurrection. Conversely, it may be a symbol of the confines of this world.