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