| 摘要 |
A developmental device for children and older, which comprises a body, which has a disc shape with a cavity in cross-sections normal to an axis of rotation of the body, in which the cavity clearly forms part of the disc. This body includes a central point of gravity when in motion. This provides a balance for containment when spun around a central point on surfaces or during flight. This invention provides developmental and educational benefits for young children and older people. |
