The current location of the array may be compared to a reference point to derive at {HEAD ~ trajectory} directing {TAIL ~ the user} to the reference point, such as an originating point 
directing
The current location of the array may be compared to a reference point to derive at { HEAD ~ trajectory } directing { TAIL ~ the user } to the reference point , such as an originating point
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH