{HEAD ~ The second portion} of the raised region is thinner than {TAIL ~ the first portion} of the raised region 
is thinner than
{ HEAD ~ The second portion } of the raised region is thinner than { TAIL ~ the first portion } of the raised region
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH