anchor.diff:  
   %% @doc Return a big random integer, but smaller than maxint32
   number() ->
  -    gen_server:call(?MODULE, number).
  +    number(1000000000).
   
   number(Max) ->
       gen_server:call(?MODULE, {number, Max}).
  
positive.code: handle_call(unique, _From, #state{is_fixed=true, unique_counter=N} = State) ->
      Id = make_unique_fixed(N),
      {reply, Id, State#state{unique_counter=N+1}};
  
  handle_call(number, _From, #state{is_fixed=true} = State) ->
      Number = random:uniform(1000000000), 
      {reply, Number, State};
  
  handle_call({number, Max}, _From, #state{is_fixed=true} = State) ->
      Number = random:uniform(Max),
  
negative.code:     Id = make_unique(),
      {reply, Id, State};
  
  handle_call({number, Max}, _From, #state{is_fixed=false} = State) ->
      Number = crypto:rand_uniform(1, Max+1),
      {reply, Number, State};
  