{TAIL ~ A first reflecting surface} of an ellipse group reflecting {HEAD ~ surface} preferably has a first focus on the light source and a second focus, capable of being inserted in or removed from an optical path from the light source to a second fixed reflecting surface 
{ TAIL ~ A first reflecting surface } of an ellipse group reflecting { HEAD ~ surface } preferably has a first focus on the light source and a second focus , capable of being inserted in or removed from an optical path from the light source to a second fixed reflecting surface
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD 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