Polymorphism

how_to_use_it.rb

vogue_magazine = Magazine.new(vogue)
self_magazine  = Magazine.new(self)

# How many pages are there in vogue magazine?
vogue_magazine.pages

# How many pages are there in self magazine?
self_magazine.pages

magazine.rb

class Magazine
  def initialize(name)
    @magazine = name
  end
  
  def pages
    @magazine.pages
  end
  
  def cover_story
    @magazine.cover_story
  end
end

self.rb

class SelfMagazine
  def initialize(self)
    @self = self
  end
  
  def pages
    @self.pages
  end
  
  def cover_story
    @self.cover_story
  end
end

vogue.rb

class VogueMagazine
  def initialize(vouge)
    @vogue = vogue
  end
  
  def pages
    @vogue.pages
  end
  
  def cover_story
    @vogue.cover_story
  end
end