Fold animation in UICollectionViewLayout

I want to achieve Fold animation when the user scrolls UICollectionView. I have UICollectionView with full-screen size cell and vertically scrolling with paging enabled. For that I've created sub-class of UICollectionViewFlowLayout which is as described below.

class FoldingFlowLayout: UICollectionViewFlowLayout {

    private let logger = Logger(subsystem: bundleIdentifier, category: "FlowLayout")

    override func prepare() {
        super.prepare()
        scrollDirection = .vertical
        minimumLineSpacing = 0
        minimumInteritemSpacing = 0
    }

    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        let attributes = super.layoutAttributesForElements(in: rect)
        attributes?.forEach { attribute in
            transformLayoutAttributes(attribute)
        }
        return attributes
    }

    override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
        return true
    }

    private func transformLayoutAttributes(_ attributes: UICollectionViewLayoutAttributes) {
        guard let collectionView = collectionView else { return }

        let contentOffsetY = collectionView.contentOffset.y
        let cellOffsetY = attributes.frame.origin.y - contentOffsetY
        let cellHeight = attributes.frame.height

        var transform = CATransform3DIdentity
        transform.m34 = -1.0 / 500.0  // Apply perspective

        if cellOffsetY < cellHeight && cellOffsetY > -cellHeight {
            let angle = (cellOffsetY / cellHeight) * .pi / 2
            transform = CATransform3DRotate(transform, angle, -1, 0, 0)
            attributes.transform3D = transform
            attributes.alpha = 1.0 - (abs(cellOffsetY) / cellHeight)
        } else {
            attributes.transform3D = CATransform3DIdentity
            attributes.alpha = 1.0
        }
    }
}

But this is not working as I expected. I want to create replica of this kind of animation. What am I missing here?