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