title: What is SKNode "origin"?
body: <p>Docs for <code>SKPhysicsBody</code> <code>bodyWithCircleOfRadius:</code> says:</p>
  
  <blockquote>
    <p>Creates a circular physics body centered on the owning node’s <strong>origin</strong>.</p>
  </blockquote>
  
  <p>So is origin a node position? Couldnt find it anywere.</p>