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