are attached angled force transfer members 53 for example by gluing snap fitting or other fastening mechanism fig6 particularly shows the inter fitting relationship of the base pan side surface 37 and the force transfer members 53 according to an illustrative embodiment as may be seen the side surface 37 has an inner horizontally disposed top step 42 and a horizontally disposed lower step 44 the angled force transfer member 53 includes a stepped edge 46 shaped to mate with the top step 42 the stepped edge 46 forms into an angled surface 48 which rests on the swept back surface 37 the angled surface 48 continues into a second step 243 which mates with the lower step 44 a slot or channel 50 is further formed in the base pan 39 and snugly receives a foot portion 34 of the angled force transfer member 53 mating surfaces of the base pan surface 37 and the force transfer member 53 may be glued snap fitted or otherwise fastened together in position in various embodiments in one embodiment the vertical support member 51 and the angled force transfer member 53 may be fabricated of extruded abs plastic and injection molded abs plastic respectively the base pan 39 may be a thermoformed abs plastic sheet other materials and fabrication techniques may of course be used in other embodiments in one embodiment.