The present invention pertains to a supporting frame, a plurality of swiveling pieces, and a plurality of movable pieces, and the above elements are constructed with each other into a sphere shape; the supporting frame disposes a first supporting stem and a second supporting stem; each swiveling piece has a top face formed in a regular polygon and a blocker located at the side thereof, and the swiveling piece installed on an extremity of the first supporting stem or the second supporting stem via a limited nail; each movable piece has a top face formed in a regular polygon, a locking portion disposed thereon, a limited portion disposed thereon, and a toothed portion disposed thereon. Accordingly, the present invention facilitates to attain a logical configuration with lower manufacturing costs and an easy mass production.