anchor.diff:                    Dict2 = lists:foldl(
                               fun({mod_start, w_1, LPN, Pg}, D) ->
                                       orddict:append(LPN, Pg, D);
  -                               ({mod_start, w_t, LPN, _Pg}, D) ->
  -                                    orddict:append(LPN, [aaaa_error_trimmed], 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, w_t, 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}
  
positive.code: -define(TRIP_bad_scan_forward, false).
  -endif.
  -ifndef(TRIP_bad_fill).
  -define(TRIP_bad_fill, true).
  -endif.
  
  initial_state() ->
  
negative.code:     %% 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_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_ft, LPN, fill, Pid};
                    ({call, Pid, {trim, LPN, will_be, ok}}) ->
                         {mod_working, w_tt, LPN, trim, Pid}
                 end,
                 fun({mod_working, _Ttn, _LPN, _Pg, _Pid}, {result, _Pid, _Res})->
                         []
  