title: Draw shadow only from 3 sides of UIView
body: <p>I've successfully implemented drawing a shadow around my <code>UIView</code> like this:</p>
  
  <pre><code>block1.layer.masksToBounds = NO;
  block1.layer.shadowOffset = CGSizeMake(0, 0);
  block1.layer.shadowRadius = 1;
  block1.layer.shadowOpacity = 0.7;
  </code></pre>
  
  <p>What now happens is I have a rectangular <code>UIView</code> and i would like to draw the shadow around it three sides, leaving the <strong>bottom</strong> side of it <em>without</em> the shadow. </p>
  
  <p>I know that I have to specify the <code>block1.layer.shadowPath</code> by creating a new <code>UIBezierPath</code> but I'm not sure how to do it.</p>
  
  <p>Obviously, setting <code>layer.shadowOffset</code> won't do the trick for me.</p>
  
  <p>Thanks in advance!</p>