title: How to define instance method in ruby dynamically?
body: <p>I want to dynamically create instance method of child class through class method of parent class.</p>
  
  <pre><code>class Foo
    def self.add_fizz_method &amp;body
      # ??? (This is line 3)
    end
  end
  
  class Bar &lt; Foo
  end
  Bar.new.fizz #=&gt; nil
  
  class Bar
    add_fizz_method do
      p "i like turtles"
    end
  end
  Bar.new.fizz #=&gt; "i like turtles"
  </code></pre>
  
  <p>What to write on line #3?</p>