The arrays of permanent magnets each have north and south poles distributed in {HEAD ~ both longitudinal and latitudinal directions} along {TAIL ~ a plane} 
along
The arrays of permanent magnets each have north and south poles distributed in { HEAD ~ both longitudinal and latitudinal directions } along { TAIL ~ a plane }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL