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