{HEAD ~ The other part} of the incident beam is refracted and transmitted through {TAIL ~ the optical member} and then totally reflected by the reflecting member to return to the optical member 
{ HEAD ~ The other part } of the incident beam is refracted and transmitted through { TAIL ~ the optical member } and then totally reflected by the reflecting member to return to the optical member
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH