{HEAD ~ The number} of {TAIL ~ the first protruding portions} 141 a equals to the number of the through holes 144 
of
{ HEAD ~ The number } of { TAIL ~ the first protruding portions } 141 a equals to the number of the through holes 144
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH