{TAIL ~ Arbiter} 16 receives {HEAD ~ requests} for access from any of a number of requesters 
{ TAIL ~ Arbiter } 16 receives { HEAD ~ requests } for access from any of a number of requesters
TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH