A first reflecting surface of {HEAD ~ an ellipse group} reflecting {TAIL ~ 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 
A first reflecting surface of { HEAD ~ an ellipse group } reflecting { TAIL ~ 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
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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