The reason why the moon waxes and wanes is because there are countless palace lanterns lit in the moon palace. They always go out during the day and stay on at night. Each wick has a time when it is on and a time when it goes out. There is a certain number of round and missing parts. The wicks flicker on and off, and they can only stay on on the full moon day of the Mid-Autumn Festival. Only during the Mid-Autumn Festival that year, one wick did not light up. The wick of this lantern enlightens my spiritual thoughts: The moon must be full every Mid-Autumn Festival, but it cannot illuminate that person. I don't want people in the world to feel sad when they see this moon. Without this full moon that makes people miss each other, people in the world don't have to think about sharing the beauty of the moon. This year the moon of the Mid-Autumn Festival was only half lit. Therefore, the wick was demoted to the earth, and went to experience the world of mortals, the ups and downs in the hustle and bustle, and suffered the pain of missing each other. He could not return to the moon palace until the day when the lamp died.