This is in contrast to an hour glass shaped feature where the transition from the bottom portion to {HEAD ~ the upper portion} of {TAIL ~ the feature} is about constant 
This is in contrast to an hour glass shaped feature where the transition from the bottom portion to { HEAD ~ the upper portion } of { TAIL ~ the feature } is about constant
OTH OTH OTH OTH OTH 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 OTH OTH OTH