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