A closure constructed for being inserted and securely retained in a portal-forming neck of a container, the closure having a substantially cylindrical shape and comprising substantially flat terminating surfaces forming the opposed ends of the closure, wherein the closure further comprises: (a) a closure precursor having a substantially cylindrical shape and comprising a lateral surface and substantially flat terminating surfaces forming the opposed ends of the closure precursor, wherein the lateral surface and the flat terminating surfaces of the closure precursor have a substantially uniform color; and (b) a decorative layer that at least partially covers at least the lateral surface of the closure precursor.