For example, {HEAD ~ a topology service} may be implemented within {TAIL ~ a virtual computing environment}, which may in turn include virtual computing instances 
implemented within
For example , { HEAD ~ a topology service } may be implemented within { TAIL ~ a virtual computing environment } , which may in turn include virtual computing instances
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH