The 10 heavenly Signs referred to the principle of the5 elements and that is basically Metal, Water, Wood, Fire and Soil.
All the 5 elements in turns have 2 properties. That is either it is Yang or it is Yin. Or it can be better known as muscular or feminine.
For Example, Likes take the elements of Wood elements.
Wood element is further divided into 2 properties, hard wood, or known as rough wood, or also knows as unpolished wood, or sometime known as virgin wood. It is called the Yang Wood. The other is known as Yin Wood, or sometime known as weak wood, or supporting wood, or refined wood and etc.
Yang wood is like the tree trunk. It is strong and unmovable. It supports the whole branches and transfer nutrition to all over the tree right to the leaves. A Yang wood person has a strong forward moving character. They can achieve great success in business. However as they are consider hard wood, it is also easy for them to hurt others or themselves. In a much more direct saying, insensitive to the surrounding and changes.
Yin wood, on the other hand is like those tweets larches on the tree trunk (hard wood). It support on the strong trunk to grow. It works as a supporting role. It can also beautify the whole trees with their tweets. A Yin wood lady is more beautiful than the yang wood lady. Yin wood lady tends to has a better sensitivities to the surrounding and are good support to the husband business.