private let layout = Builder<UICollectionViewFlowLayout>()
    .minimumInteritemSpacing(0)
    .minimumLineSpacing(0)
    .sectionInset(.zero)
    .scrollDirection(.horizontal)
    .build()
    
private(set) lazy var containerView = Builder<BaseCollectionView>()
    .showsHorizontalScrollIndicator(false)
    .showsVerticalScrollIndicator(false)
    .collectionViewLayout(layout)
    .isPagingEnabled(true)
    .bounces(true)
    .backgroundColor(.clear)
    .build()

final class CubeContainerCell: BaseCollectionViewCell {
    var viewController: UIViewController?
    
    override func initSetup() {
        super.initSetup()
        
        clipsToBounds = false
        contentView.clipsToBounds = false
    }
    
    func applyTransform(_ percent: CGFloat) {
        ...
    }
}

extension CubeTransitionViewController: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { accounts.count }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard
            let cell = collectionView.dequeue(CubeContainerCell.self, for: indexPath),
            let context = self.accounts.at(indexPath.item)
        else { fatalError("wrong index") }
        
        cell.viewController = try! userCheckinsFactory.build(with: context)
        cell.viewController?.loadViewIfNeeded()
        
        return cell
    }
}

extension CubeTransitionViewController: UICollectionViewDelegate {
    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        guard let cell = cell as? CubeContainerCell, let viewController = cell.viewController else { return }
        self.addChild(vc: viewController, bindedTo: cell.contentView)
    }
    
    func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        guard let cell = cell as? CubeContainerCell, let viewController = cell.viewController else { return }
        self.removeChild(viewController)
    }
}

extension CubeTransitionViewController: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout: UICollectionViewLayout, sizeForItemAt: IndexPath) -> CGSize {
        collectionView.frame.size
    }
}

extension CubeTransitionViewController: UIScrollViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        transformViewsInScrollView(scrollView)
    }
    
    func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) {
        scrollView.isUserInteractionEnabled = false
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        scrollView.isUserInteractionEnabled = true
    }
    
    func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
        scrollView.isUserInteractionEnabled = true
    }
    
    func transformViewsInScrollView(_ scrollView: UIScrollView) {
        let svWidth = scrollView.frame.width
        
        for index in 0 ..< mainView.containerView.visibleCells.count {
            guard let view = mainView.containerView.visibleCells[index] as? CubeContainerCell else { continue }
            
            let svCenter = scrollView.frame(in: view).center.x
            let cellCenter = view.frame(in: view).center.x
            
            let xDiff = svCenter - cellCenter
            
            view.applyTransform(xDiff / svWidth)
        }
    }
}

func applyTransform(_ percent: CGFloat) {
    let view = self.contentView
        
    let maxAngle: CGFloat = 60.0
    let rad = percent * maxAngle * CGFloat(Double.pi / 180)
        
    var transform = CATransform3DIdentity
    transform.m34 = 1 / 500
    transform = CATransform3DRotate(transform, rad, 0, 1, 0)
        
    view.layer.transform = transform
        
    let anchorPoint = percent > 0 ? CGPoint(x: 1, y: 0.5) : CGPoint(x: 0, y: 0.5)
        
    var newPoint = CGPoint(
        x: view.bounds.size.width * anchorPoint.x,
        y: view.bounds.size.height * anchorPoint.y
    )
    var oldPoint = CGPoint(
        x: view.bounds.size.width * view.layer.anchorPoint.x,
        y: view.bounds.size.height * view.layer.anchorPoint.y
    )
        
    newPoint = newPoint.applying(view.transform)
    oldPoint = oldPoint.applying(view.transform)
        
    var position = view.layer.position
    position.x -= oldPoint.x
    position.x += newPoint.x
        
    position.y -= oldPoint.y
    position.y += newPoint.y
        
    view.layer.position = position
    view.layer.anchorPoint = anchorPoint
        
    view.alpha = 1 - (-percent).clamped(0, 1)
}