Yin and yang and yang are bound together as parts of a mutual whole (for example, there cannot be the bottom of the foot without the top). A way to illustrate this idea is to postulate the notion of a race with only men or only women; this race would disappear in a single generation. Yet, men and women together create new generations that allow the race they mutually create (and mutually come from) to survive. The interaction of the two gives birth to things, like manhood. Yin and yang transform each other: like an undertow in the ocean, every advance is complemented
Yin and yang yang are represented by broken and solid lines: yin is broken (⚋) and yang is solid (⚊). These are then combined into trigrams, which are more yang ("e.g." ☱) or more yin ("e.g." ☵) depending on the number of broken and solid lines ("e.g.", ☰ is heavily yang, while ☷ is heavily yin), and trigrams are combined into hexagrams ("e.g." ䷕ and ䷟). The relative positions and numbers of yin and yang lines within the trigrams determines the meaning of a trigram, and in hexagrams the upper trigram is considered yang with respect to the lower trigram, yin, which allows