Furthermore, the separation between a pair of {TAIL ~ adjacent rows} need not be equal to the separation between {HEAD ~ another pair} of adjacent rows 
Furthermore , the separation between a pair of { TAIL ~ adjacent rows } need not be equal to the separation between { HEAD ~ another pair } of adjacent rows
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH