{TAIL ~ The pattern} of {HEAD ~ illuminated pixels} changes smoothly with time to produce the required uniform high quality grey level 
{ TAIL ~ The pattern } of { HEAD ~ illuminated pixels } changes smoothly with time to produce the required uniform high quality grey level
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