{HEAD ~ This tray} 15 comprises a well 45 for holding markers and the like, and upstanding therefrom a pair of {TAIL ~ spaced apart flanges} 46 and 47 dimensioned for entry into the channel 41 of the extrusion 37 
{ HEAD ~ This tray } 15 comprises a well 45 for holding markers and the like , and upstanding therefrom a pair of { TAIL ~ spaced apart flanges } 46 and 47 dimensioned for entry into the channel 41 of the extrusion 37
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH