Feng Shui loves to talk about "evil spirits", and the so-called "evil spirits" are threats in plain English. According to the theory of geomantic omen, the clock has the function of dispelling evil spirits in geomantic omen, which is similar to the "geomantic wheel". If there are sharp or dirty objects outside the house (measured by the area that indoor people can see), they are not "evil spirits" but threats and need to be eliminated. The specific method is to hang a clock on the wall opposite the door and window where you see evil things, and face the door and window to turn evil into good luck.