Channels 44 accommodate {TAIL ~ webs} 30 and open portions 46 accommodate {HEAD ~ first and second ends} 26 and 28 of the grid 20 
Channels 44 accommodate { TAIL ~ webs } 30 and open portions 46 accommodate { HEAD ~ first and second ends } 26 and 28 of the grid 20
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH