The Moon is Binary in Nature

Having heard the poem, Monkey went up to him and said, "Master, you only know about the moon's beauty, and you're homesick too. You don't know what the moon's really about. It's like the carpenter's line and compasses−−it keeps the heavenly bodies in order. On the thirtieth of every month the metal element of its male soul has all gone, and the water element of its female soul fills the whole disk. That is why it goes black and has no light. That's what is called the end of the old moon. ...