respond_to_missing?(method, _)

rps.rb

class RockPaperScissorsGame
  PATTERNS ||= [:rock, :paper, :scissors]

  def respond_to_missing?(method, _)
    PATTERNS.include?(method) || super(method)
  end

  def method_missing(guess, *args, &block)
    if PATTERNS.include?(guess)
      puts "You played #{guess}!"
    else
      super(guess, *args, &block)
    end
  end
end

game = RockPaperScissorsGame.new
game.rock
p game.respond_to?(:rock)