title: How to create a rotating circle?
body: <p>I'm trying to make a simple "rotating gear animation." Basically, I want to put a circle on the screen at a certain position, and give this circle an image of gear (or just make the image rotating without creating a circle at first). Also, the gear should keep rotating. How can I achieve that? </p>
  
  <p>I'm beginner to ios development. If anyone can provide a simple sample code, I will really appreciate that!</p>