title: Flickering background to Swift Sprite-kit app
body: <p>I would like to create background of this style to my sprite-kite app written in Swift: <a href="https://www.youtube.com/watch?v=o1Fu8GOKGes" rel="nofollow">https://www.youtube.com/watch?v=o1Fu8GOKGes</a></p>
  
  <p>but can't think of how that is created. All help to get started is gretly appreciated!</p>