{HEAD ~ Each} of the gate structures may interpose a source region and {TAIL ~ a drain region} 
{ HEAD ~ Each } of the gate structures may interpose a source region and { TAIL ~ a drain region }
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL