{TAIL ~ the waist} is centered at {HEAD ~ an axial distance} from the front end of the tip; and 
{ TAIL ~ the waist } is centered at { HEAD ~ an axial distance } from the front end of the tip ; and
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH