anchor.diff:  
   %% Pick and return a random element from a given list
   choice(List) ->
  +    random:seed(now()),
  +    timer:sleep(random:uniform(?MAX_RANDOM_SLEEP)),
       Maximum = length(List),
       Element = random:uniform(Maximum),
       lists:nth(Element, List).
  
positive.code:             {NewPortfolio, NewTransactions} = transaction(
                  choice([buy, sell]), Symbol, Price, 1, Portfolio, Transactions
              ),
              io:format("~p~n", [dict:to_list(NewPortfolio)]),
              io:format("~p~n", [NewTransactions]),
              io:format("~n"),
  
negative.code: -define(MAX_LISTINGS, 5).
  -define(MAX_BROKERS, 3).
  -define(TICKER_INTERVAL, 1000).
  -define(MAX_RANDOM_SLEEP, 100).
  
  
  %%%----------------------------------------------------------------------------
  