Each FIFO buffer 710 a 710 d accepts every fourth or Mth count for {HEAD ~ a total} of {TAIL ~ N counts} 
of
Each FIFO buffer 710 a 710 d accepts every fourth or Mth count for { HEAD ~ a total } of { TAIL ~ N counts }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL