Calisto Armillary Bookends

An ancient Greek may have invented this type of sphere. It was made from a shell of spinning and graduated circles, representing the ecliptic, equator, parallels, and meridians. If that's confusing -- it's a ball form with the sun in the center. The earth used to be in there when the consensus was that humans were the center of the universe. Our bookends look like pewter placed on right angles of a black, marble-like material.