delineated the duality of the world. Half of an ideal circle is dark though half is light. On the light side is dark dot or eye, though on the dark a light dot sits even with the dark dot. Yin and Yang stand as opposites, still they are measure for measure accurately the same. This describes the philosophy that no one thing subsists without its contradiction. For example, night does could not subsist without day. Yin and yang tattoos also are a symbol of how they can transmute into one some other just as night becomes day, and cold gives way to warmth.
Yin and yang sustain each other even as they consume one some other. The yin can be seen as pleasure and yang unhappiness. No one would know pleasure if they had not experienced unhappiness and so on. This decodes to a fine tattoo because it is a contrasting image that intends accurately what it looks to intend.