The beam reaches the far end of the hole, and is reflected from {HEAD ~ a surface} located at or adjacent {TAIL ~ the far end} of the hole to illuminate the interior of the hole 
adjacent
The beam reaches the far end of the hole , and is reflected from { HEAD ~ a surface } located at or adjacent { TAIL ~ the far end } of the hole to illuminate the interior of the hole
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH