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