Neolithic Chinese objects in the form of a flat disk with a hole in the center. The term bi is applied to wide disks with proportionately small central holes, made from jade or other stone, and found at burial sites. There is much speculation on the function of these objects, though they are generally thought to represent the heavens or the sun. Bi have continued to be used as a form of regalia and as decorative objects well into the late nineteenth and early twentieth centuries. They are often seen as related to the "cong (ceremonial vessel)," which represented the earth.