{HEAD ~ The data} is supplied from {TAIL ~ the buffer} 91 to the image comparator 92 
is supplied from
{ HEAD ~ The data } is supplied from { TAIL ~ the buffer } 91 to the image comparator 92
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH