         navigationController?.navigationBar.barTintColor = UIColor.whiteColor()
     }
 
+    func showPresentation() {
+        let viewController = UITableViewController()
+        viewController.title = "Presentation"
+        let navigationController = UINavigationController(rootViewController: viewController)
+        navigationController.modalPresentationStyle = .Custom
+        navigationController.transitioningDelegate = self
+
+        presentViewController(navigationController, animated: true, completion: nil)
+    }
 }
 
 extension ViewController: UICollectionViewDelegate {


        return nil
    }
}
        layout.itemSize = CGSize(width: CGRectGetWidth(collectionView!.frame), height: 200)
        collectionView?.collectionViewLayout = layout
        collectionView?.registerClass(CollectionViewCell.self, forCellWithReuseIdentifier: "cell")

        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "overlay", style: .Plain, target: self, action: "showPresentation")
    }

    override func viewWillAppear(animated: Bool) {
