An invocation to Card.new should result in a random card.

cards.rb

class Card
  def initialize(rank = nil, suit = nil)
    if suit.nil?
      @suit = ['♠', '♣', '♥', '♦'].sample
    else
      @suit = suit
    end

    if rank.nil?
      @rank = ((2..10).to_a + ["A", "J", "Q", "K"]).sample
    else
      @rank = rank
    end
    puts "Create a new card: #{@rank} of #{@suit}"
  end
end