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