Preferably a selected object will be highlighted in some way, for example by a change in color or variation in {HEAD ~ the degree} of {TAIL ~ luminosity} on the screen to confirm the operators selection 
Preferably a selected object will be highlighted in some way , for example by a change in color or variation in { HEAD ~ the degree } of { TAIL ~ luminosity } on the screen to confirm the operators selection
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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