{HEAD ~ A locked state} managed by the blocker greatly reduces corner cases and simplifies {TAIL ~ solutions} in the few remaining corner cases 
greatly simplifies
{ HEAD ~ A locked state } managed by the blocker greatly reduces corner cases and simplifies { TAIL ~ solutions } in the few remaining corner cases
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH