# Polymorphism (Duck Typing)
class Bird
 def tweet(bird_type)
 bird_type.tweet # the secret is here
 end
end
class Cardinal < Bird
 def tweet
 puts "Tweet tweet"
 end
end
class Parrot < Bird
 def tweet
 puts "Squawk"
 end
end
generic_bird = Bird.new
generic_bird.tweet(Cardinal.new)
generic_bird.tweet(Parrot.new)
# But what is the benefit of this??
# I have no idea