title: UIImageview rotation animation
body: <p>I want to apply an animation to two <code>UIImageViews</code>. The idea is for image one to flip horizontally by 90 degrees and then image two to complete the rotation. Think of it as a coin spinning: Head side (image one) faces forward -> turn 90 degrees -> Tail side (image two) rotates to face forward. I can do the first half of the animation but I am stuck on the second.</p>
  
  <pre><code>[UIView animateWithDuration:1.0f animations:^{
      image1.transform = CGAffineTransformMakeScale(-0.01, 1);
  } completion: ^(BOOL finished) {
      // How can I make image 2 to rotate out as if it initially was already rotated by 90 degrees?
  }];
  </code></pre>