The first mirror is configured to receive a first incident laser beam from the first end and to reflect {HEAD ~ a first reflected beam} to reflect as a third reflected beam from {TAIL ~ the third mirror} 
to reflect from
The first mirror is configured to receive a first incident laser beam from the first end and to reflect { HEAD ~ a first reflected beam } to reflect as a third reflected beam from { TAIL ~ the third mirror }
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 HEAD REL REL OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL