Bingo number generation

bingo.rb

class Bingo

  MAX_NUM = 50
  NUMBERS_IN_CARDBOARD = 10
  CARDBOARD_IN_GAME = 15

  def with_repetitions? cardboard
    cardboard.inject do |prev, current|
        return true if prev == current
        current
    end
    false
  end

  def cardboard
    c = NUMBERS_IN_CARDBOARD.times.map { rand(MAX_NUM)+1  }.sort
    return c unless with_repetitions? c
    cardboard
  end

  def puts_cardboard cardboard
    cardboard.each { |n| print "#{n}, " }
    print "\n"
  end

  def game
    CARDBOARD_IN_GAME.times.map { cardboard }
  end

  def puts_game game
    game.each { |cardboard| puts_cardboard cardboard }
  end

end

bingo = Bingo.new
bingo.puts_game bingo.game