The vertical members have exposed exterior surfaces that are preferably generally flush with {HEAD ~ the exterior surface} of {TAIL ~ the fixed panes} 
of
The vertical members have exposed exterior surfaces that are preferably generally flush with { HEAD ~ the exterior surface } of { TAIL ~ the fixed panes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL