One way of dealing with this is to query {TAIL ~ the User} regarding {HEAD ~ the source} of the environmental light by a software application operating at the host computer coupled to the display 
One way of dealing with this is to query { TAIL ~ the User } regarding { HEAD ~ the source } of the environmental light by a software application operating at the host computer coupled to the display
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH