Piece of jewellery of generally toroidal shape having an annular enclosed space (18) closed upon itself of which the outer wall (1) and/or inner wall (2) are at least partly transparent. This enclosed space (18) holds decorative elements (13) freely moving inside of it....http://www.google.es/patents/US7823415?utm_source=gb-gplus-sharePatente US7823415 - Piece of jewelry with mobile elements
