title: How can I animate the height of a CALayer with the origin coming from the bottom instead of the top?
body: <p>I want to animate a simple CALayer to move up and down in response to incoming data (bars on a graphic equaliser)</p>
  
  <p>The CALayer should remain <em>fixed</em> along the bottom and move up and down as the height is animated.</p>
  
  <p>Can anybody advise on the best way to achieve this without having to animate the origin y coord as well as the height?</p>