title: Present modal view controller over modal view controller
body: <p>I have a view controller VC1 that is presented modally over full screen from some other VC0. In my storyboard I have a modal segue from VC1 to VC2 also presenting over full screen. When in my app I can plainly see VC2 over VC1 over VC0, because some parts of their views are transparent. Perfect.</p>
  
  <p>However, I'm going to reuse VC2 many times so I don't want to have a segue to it for each controller in my storyboard, so I want to accomplish this same thing programmatically. However, when I call presentViewController:animated:completion in VC1 to present VC2, the view of VC1 disappears when the modal transition is complete. When VC2 is dismissed, the view of VC1 reappears when the transition animation is complete.</p>
  
  <p>How can I get the same effect programmatically as when I'm using the storyboard segue?</p>