communicating, by the display, to the user substantially continuously during {HEAD ~ the moving a direction} back to {TAIL ~ the fixed staring point} 
communicating , by the display , to the user substantially continuously during { HEAD ~ the moving a direction } back to { TAIL ~ the fixed staring point }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL