title: Decreasing NSTimer interval every time it runs
body: <p>I want my <code>NSTimer</code> to speed up each time it's run:</p>
  
  <pre><code>-(void)runtimer {
     int delay = delay - 1;
     [NSTimer scheduledTimerWithTimeInterval:(delay) 
                                      target:self 
                                    selector:@selector(timerTriggered:) 
                                    userInfo:nil 
                                     repeats:YES];
  
  }
  </code></pre>
  
  <p>But this doesn't work. How can I make the delay keep getting smaller and smaller?</p>