Most everyone is familiar with this symbol. It shows several elements, such as change, movement, dark, light, circular, returning, and complementary balance. The two dots are representation of when one reaches the outer limit of a path and it then must revers and come back on itself.
Yang is associated with; Heaven, Sunny Light, Sun, Day, Fire, Heat, Hollow, Dryness, Expansive, Masculine. Yin is associated with; Earth, Cloudy, Dark, Moon, Night, Water, Cold, Solid, Dampness, Receptive, Feminine.