{TAIL ~ The frame} may comprise a base frame and a operating leaf frame overlying {HEAD ~ the base frame} 
{ TAIL ~ The frame } may comprise a base frame and a operating leaf frame overlying { HEAD ~ the base frame }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD