title: Creating a simple Simon clone: How to wait between updates?
body: <p>I'm learning Cocoa/Objective-C/iPhone SDK, and as a simple project to apply what I've learned, I wanted to create a simple version of the Simon game of old.  Four colored buttons, you're shown a sequence (Red, Green, Blue, Red, etc.) and you have to repeat the sequence back.</p>
  
  <p>I believe I have most of it figured out, save one piece: showing the sequence to the user.  Specifically, how to implement the delay between highlighting the button &amp; setting it back to normal after 200ms.  </p>
  
  <p>If I sleep in the main run loop, the update doesn't happen properly (even if I explicitly call <code>setNeedsDisplay</code>).  If I spawn off a new thread, things get complicated quickly as my class method needs to refer back to UI elements (instant variables). </p>
  
  <p>Any advice?</p>