Set including five distinct elements based on a hollow cube

Claim 1

A set of toy building elements, each said element being based on a hollow cube and having at least two walls corresponding to sidewalls of said cube, said set comprising at least one of each of the following elements: a. a building element consisting of two joined walls corresponding respectively to two mutually adjacent sidewalls of said cube, b. a building element consisting of three joined walls corresponding respectively to two mutually opposite sidewalls of said cube and to a third sidewall of said cube adjacent to both said opposite sidewalls, c. a building element consisting of three joined walls corresponding respectively to two mutually adjacent sidewalls of said cube and to a third sidewall of said cube adjacent to both of saiD two mutually adjacent sidewalls, d. a building element consisting of four walls mutually connected along edges thereof so as to form a tube having a square cross-section, said four walls corresponding respectively to four sidewalls surrounding an axis of said cube, e. a building element consisting of four joined walls corresponding respectively to two mutually adjacent sidewalls of said cube and to two mutually opposite sidewalls of said cube, each said opposite sidewall being adjacent with respect to both said mutually adjacent sidewalls, all of said walls being flat, of equal and uniform thickness.