I’m beginning to understand a little of Chinese celestial architecture. Heaven (tian) is a circle, so the moon doors and round windows which you see in Chinese architecture are auspicious, since they have something to do with heaven. The bell is the sound of heaven. Every town worth its name has a bell tower, and a bell which tolls the beginning of the day.
The earth (di) is square, and the sound of a drum is the sound of the earth. No self-respecting town would be without a drum tower to mark the end of the day. The two words together (tiandi) mean everything, the universe. So what does the window in the photo below symbolize?
The tombs of emperors are laid out with the entrance and the buildings in it arranged within a manicured square. The burial mound will be a hill which is round in shape. The place where the two touch contains a Tower of the Soul. The entrance will face south, and there will be water in front. At the back will be mountains or a tortoise. All laid out according to the mystical principles of Fengshui.