anchor.diff:  %% them by name later. Command dispatch table is a part of our process
   %% state, so we couldn't just use short function references (fun
   %% name/X) here, or we'll lose ability to reload changed code.
  --export([cmd_look/4, cmd_go/4, cmd_get/4, cmd_quit/4]).
  +-export([cmd_look/4, cmd_go/4, cmd_get/4, cmd_quit/4, cmd_help/4]).
   
   %% Very simple console user UI. 
   -export([console_play/0]).
  
positive.code: move_to(NewLocation, #{edges := Edges} = State) ->
      State#{location := NewLocation, location_edges := maps:get(NewLocation, Edges)}.
  
  unlines(ListOfStrings) ->
      list_to_binary(string:join(ListOfStrings, "\n")).
  
  
negative.code:     maps:get(Location, Rooms).
  
  describe_directions(#{location_edges := Edges}) ->
      unlines(
        [ io_lib:format("There is a ~s going to ~s from there", [Direction, Room])
          || {Direction, Room} <- maps:to_list(Edges)
        ]).
  
  describe_objects(#{location := Location, objects := Objects}) ->
      ObjectsInCurrentLocation =
  