The two sets of {TAIL ~ two coils} are positioned on {HEAD ~ two different sides} of the array 
The two sets of { TAIL ~ two coils } are positioned on { HEAD ~ two different sides } of the array
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH