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