Each C shaped channel 18 includes {HEAD ~ a pair} of opposed generally L shaped legs 34 and {TAIL ~ an interconnecting portion} 36 extending between legs 34 
Each C shaped channel 18 includes { HEAD ~ a pair } of opposed generally L shaped legs 34 and { TAIL ~ an interconnecting portion } 36 extending between legs 34
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH