Similar to the first channel section 12, the channel section 14 may be formed of a metal channel having {HEAD ~ a substantially semi circular cross section}, which is curved to form {TAIL ~ the shape} of an arc extending through a quarter circle 
is curved to form
Similar to the first channel section 12 , the channel section 14 may be formed of a metal channel having { HEAD ~ a substantially semi circular cross section } , which is curved to form { TAIL ~ the shape } of an arc extending through a quarter circle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH