In {TAIL ~ an embodiment}, the region 38 has depth greater than {HEAD ~ the region} 34 
In { TAIL ~ an embodiment } , the region 38 has depth greater than { HEAD ~ the region } 34
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH