Bingo's timer that calls numbers no longer repeats numbers. Throws an exception after it calls every number, because timer doesn't stop. This isn't a concern for the actual game, though, because there's no way for every number to be called as long as the number of cards > the number of available bingos. The pool of available numbers is now an ArrayList that has the number removed when called. This avoids the program having to keep guessing a random until until it finds one that hasn't been called yet. Removing an element from an ArrayList with only 75 elements has a trivial cost.