Each L shaped leg 34 includes a transversely extending lip 38 with a keying arrangement in {TAIL ~ the form} of a plurality of {HEAD ~ slots} 40 formed therein 
Each L shaped leg 34 includes a transversely extending lip 38 with a keying arrangement in { TAIL ~ the form } of a plurality of { HEAD ~ slots } 40 formed therein
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH