title: Can categories be inherited?
body: <p>Say I have a class Parent and the child is Child1 and Child2.</p>
  
  <p>I declare Parent+ParentCategory and then I declare a method:</p>
  
  <pre><code>-(void) Redraw;
  </code></pre>
  
  <p>Later I want the <code>Redraw</code> function of Child1 to be different than the <code>Redraw</code> function of Child2.</p>
  
  <p>Can I declare Child1+Child1Category and then override the </p>
  
  <pre><code>-(void) Redraw
  </code></pre>
  
  <p>Can <code>-(void)Redraw</code> of Child1 call the function in the parent category?</p>
  
  <p>Can that be done?</p>
  
  <p>What would be good approach?</p>
  
  <p>I know classes can inherit each other. I know protocol can extend each other. I wonder why category doesn't?</p>