{TAIL ~ The needle} 136 and the magnetic bar 132 are separated by {HEAD ~ a predetermined interval}  
{ TAIL ~ The needle } 136 and the magnetic bar 132 are separated by { HEAD ~ a predetermined interval }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH