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