In a preferred embodiment, the first sheet of material 12a is a light transmitting material constructed from a plastic film (Vifan BT medium slip biaxially oriented polypropylene film (clear)), having a thickness in a range from between about 0.4 mil and about 0.9 mil, available from Vifan Canada, Inc., Vifan street, Lanoraie d'Autray, Quebec, Canada JOK 1EO. An alternative plastic film (Hercules