   
   // MARK: - SwarmRenderer
   @IBOutlet weak var renderView: SwarmRenderView!
-  var isRunning = false
+  var isRunning = false {
+    didSet {
+      resumeButton.isHidden = isRunning
+    }
+  }
   var steps: Int {
     return 3
   }

      return
    }
    resume()
    resumeButton.isHidden = true
  }

  @IBAction func share(sender: AnyObject!) {

      return
    }
    pause()
  }

  @IBAction func resume(sender: AnyObject!) {
