anchor.diff:      %% Use the following atoms to denote transitions ("Ttn") by an LPN:
       %% w_0 = not written yet, error_unwritten
       %% w_1 = written successfully, {ok, binary::()}
  -    %% w_t = trimmed, error_trimmed
  +    %% w_ft = fill trimmed, error_trimmed
  +    %% w_tt = trim trimmed, error_trimmed
   
       Mods = eqc_temporal:stateful(
                  fun({call, Pid, {append, Pg, will_be, LPN}}) ->
                          {mod_working, w_1, LPN, Pg, Pid};
                     ({call, Pid, {fill, LPN, will_be, ok}}) ->
  -                       {mod_working, w_t, LPN, fill, Pid};
  +                       {mod_working, w_ft, LPN, fill, Pid};
                     ({call, Pid, {trim, LPN, will_be, ok}}) ->
  -                       {mod_working, w_t, LPN, trim, Pid}
  +                       {mod_working, w_tt, LPN, trim, Pid}
                  end,
                  fun({mod_working, _Ttn, _LPN, _Pg, _Pid}, {result, _Pid, _Res})->
                          []
  
positive.code: -define(TRIP_bad_scan_forward, false).
  -endif.
  -ifndef(TRIP_bad_fill).
  -define(TRIP_bad_fill, true).
  -endif.
  
  initial_state() ->
  
negative.code:                   Dict2 = lists:foldl(
                              fun({mod_start, w_1, LPN, Pg}, D) ->
                                      orddict:append(LPN, Pg, D);
                                 ({mod_start, WType, LPN, _Pg}, D)
                                   when WType == w_ft; WType == w_tt ->
                                      orddict:append(LPN, [error_trimmed], D)
                              end, Dict1, [X || X={mod_start,_,_,_} <- StEnds]),
                    Dict3 = lists:foldl(
                              fun({mod_end, w_1, LPN, Pg}, D) ->
                                      orddict:store(LPN, [Pg], D);
                                 ({mod_end, WType, LPN, _Pg}, D)
                                   when WType == w_ft; WType == w_tt ->
                                      orddict:store(LPN, [error_trimmed], D)
                              end, Dict2, [X || X={mod_end,_,_,_} <- StEnds]),
                    {{TS1, TS2, [{values, Dict3}]}, Dict3}
  