Therefore, {HEAD ~ a proper replacement} can be achieved at the latter step S151 by making {TAIL ~ the profiles} at the line L side coincide together 
Therefore , { HEAD ~ a proper replacement } can be achieved at the latter step S151 by making { TAIL ~ the profiles } at the line L side coincide together
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH