title: Multiple Inheritance in Ruby?
body: <p>I thought that Ruby only allowed single inheritance besides mixin. However, when I have class <code>Square</code> that inherits class <code>Thing</code>, <code>Thing</code> in turn inherits <code>Object</code> by default.</p>
  
  <pre><code>class Thing
  end
  
  class Square &lt; Thing
  end
  </code></pre>
  
  <p>Doesn't this represent multiple inheritance?</p>