yin and yang are not total opposites

Darth Vadar has the seed of goodness,and Luke has the potential to follow
his father to the dark side.Like Luke and his father,yin and yang are not total opposites,they are relative to each other.Taoists believe that the universe is made up of energies, vibrations, and matter,which behave differently in different contexts.Something can be yin or yang depending on,well, depending on lots of things.So, while wheat that's growing is yang,when it's being reaped, it's yin.A wave's crest is yang,and the trough is yin.