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