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