The device includes {HEAD ~ a first subset} of light modulators and {TAIL ~ a second subset} of light modulators 
The device includes { HEAD ~ a first subset } of light modulators and { TAIL ~ a second subset } of light modulators
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH