The Yin and Yang symbol with white representing Yang and black representing Yin.
The symbol is a visual depiction of the intertwined duality of all things in nature, a common theme in w:Taoism. 
It is believed to be derived from the 14th century Tiandi Zhiran Hetu (Heaven and Earth’s Natural Diagram of the River), Hetu (Diagram of River), Luoshu (Chart of Luo), Xiantian tu (Diagram of Preceding Heaven) and Taijitu (太極圖) (Diagram of the Ultimate Power).

Here the diagram is shown against a feather edged grey background to ensure clarity when displayed over black or white.
This vector image was created with Inkscape by Klem, and then manually edited by Mnmazur
Klem