of the pivotal support for the leg members 26 is shown in fig5 7 here a closed housing structure replaces the open channel structure heretofore described this box like closed housing serves to replace the leg support wall 22 in fig1 4 with two spaced and opposing leg support walls 36 and 38 respectively in this embodiment leg support members 26 39 can be smaller dimensioned but of rectangular cross section for effecting maximum stability so that both leg members can fit adjacent to each other between end wall 48 and end plate member 40 see fig5 and fig6 each of the leg support walls 36 38 may be provided with suitable cut out portions 44 to allow the leg members 26 39 to extend fully so that the angled bearing face 28 39 thereof similar to the structure shown in fig2 a rests flush against its respective support wall as shown in fig7 fig8 shows a particular arrangement of reflective elements preferably rigid reflex reflective elements incorporating a corner cube design as taught in u s pat no 835 648 nov 13 1906 and more recently in u s pat no 3 684 348 aug 15 1972 according to the present invention each element is either a 4 inch square 51 of a triangular half square 50 the elements 50 51 are molded in different colors to produce contrasting stripes without the need for painting by suitably riveting half or full squares to the panel by means of rivets 52 the entire panel is covered as shown thus a panel measuring 81 2 inches high and.