This is for memory, it is a concept. For example, why is the left hand called the left hand? Right hand is called right hand? The two stars of the flying star are flying out through the two stars of the mountain. If the right side is a directional star and the left side is a mountain star, it is also possible. As long as you can fly in your hand.
Usually sitting on the mountain, sitting behind the mountain, facing the mountain in front. So this is the way to tell. And easy to remember. Actually, it's all small things, and you complicated it.