The coils are in {TAIL ~ the form} of {HEAD ~ spirals} and extend in a predetermined direction 
The coils are in { TAIL ~ the form } of { HEAD ~ spirals } and extend in a predetermined direction
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH