{TAIL ~ Each grey level signal} causes a particular proportion of {HEAD ~ pixels} to be illuminated, in order to produce a particular grey level 
{ TAIL ~ Each grey level signal } causes a particular proportion of { HEAD ~ pixels } to be illuminated , in order to produce a particular grey level
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH