US Patent 8020518 Multi-configuration animal play structure

A multi-configuration structure including a base member, a plurality of cylindrical tubular spacers and a plurality of shelf members. The structure is assembled by threadably inserting the male connectors of a first set of spacers into the threaded recesses of the base member, aligning the assembly holes of a shelf member with the threaded recesses of the first set of spacers, inserting the threaded male connectors of a second set of spacers into and through the assembly holes of the shelf member and threadably inserting the male connectors into the threaded recesses of the first set of spacers, installing additional shelf members, spacers and walls in a configuration desired by the user.