{HEAD ~ The ends} of {TAIL ~ the channel} and the corresponding end caps may be either square or slanted 
of
{ HEAD ~ The ends } of { TAIL ~ the channel } and the corresponding end caps may be either square or slanted
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH