The primary objective of the present invention is to provide a bidirectional projector, which may project {HEAD ~ slides} onto {TAIL ~ two screens} in the same time 
onto
The primary objective of the present invention is to provide a bidirectional projector , which may project { HEAD ~ slides } onto { TAIL ~ two screens } in the same time
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH