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: %% Length of session keys, used for the cookies, must be unique
  -define(ID_LENGTH,20).
  -define(OPTID_LENGTH,6).
  
  %% Range of random numbers returned
  -define(RANDOM_RANGE, 2000000000).
  
  %% gen_server exports
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
  
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};
  