One such application is to control {HEAD ~ the amount} of {TAIL ~ light}, ambient or otherwise, entering through a window 
One such application is to control { HEAD ~ the amount } of { TAIL ~ light } , ambient or otherwise , entering through a window
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH