The shaping means is then moved proximally along a first predetermined contour, to {HEAD ~ a proximal area} on the tube, and then along a second predetermined contour, symmetrical to the first predetermined contour, back to the point of {TAIL ~ entry} 
The shaping means is then moved proximally along a first predetermined contour , to { HEAD ~ a proximal area } on the tube , and then along a second predetermined contour , symmetrical to the first predetermined contour , back to the point of { TAIL ~ entry }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL