The Taijitu is far better known by the name of the principle which it represents, Yin and Yang - a concept originating in ancient China which describes all things as being composed of two opposing but complementary forces. From Wikipedia:

One cannot exist without the other. For example, day cannot exist without night. Light cannot exist without darkness.

How fitting that it should appear, as if by magic, here in a pool of water on the edge of the Saharan desert.

Thanks to Carlos da Costa F.