{HEAD ~ an optical lens}, wherein {TAIL ~ the image beam} emits to the optical lens and a part of the image beam passes through the optical lens to form a first projecting beam, and a part of the image beam is reflected by the optical lens to form a second projecting beam 
{ HEAD ~ an optical lens } , wherein { TAIL ~ the image beam } emits to the optical lens and a part of the image beam passes through the optical lens to form a first projecting beam , and a part of the image beam is reflected by the optical lens to form a second projecting beam
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH