 
 import UIKit
 
-class ViewController: UIViewController {
+class CubicCollectionViewController: UIViewController {
 
     let maxAngle: CGFloat = 60
     @IBOutlet weak var collectionView: UICollectionView!

    }
}

extension ViewController: UIScrollViewDelegate {
    private func angleForCell(at indexPath: IndexPath) -> CGFloat {
        let p = transitionProgressForCell(at: indexPath)
        return maxAngle * p

}


extension CubicCollectionViewController: UICollectionViewDataSource {
    final func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
