{TAIL ~ The two sub regions} of center region 34, in an embodiment, are connected together external of {HEAD ~ the sub regions} 
{ TAIL ~ The two sub regions } of center region 34 , in an embodiment , are connected together external of { HEAD ~ the sub regions }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD