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