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