Hi guys, I've spent a day trying to complete the challenge but I'm stuck at flipping the card back part...I've generated buttons with imageView for the cards and they mostly work except for this part: if I flip two cards that don't match they flip back but, if I select the first card again it's not flipping back for some reason. I think it's because I'm misusing the viewWithTag method to keep track of the previous button views. Could I get a hint? Below is my code, beware, it's a mess... Thank you!

    @objc func cardTapped(_ sender: UIButton) {

        guard let title = sender.titleLabel?.text else { return }
        //test flipping
        let someView = createflippedLabel(text: title)
        someView.tag = 1984
        sender.addSubview(someView)
        someView.isHidden = true

        if !firstCardFlipped {
            assignFirstCard(card: title)
            previousButton = sender

            DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                UIView.transition(from: sender.imageView!, to: someView, duration: 0.3, options: [.transitionFlipFromRight, .showHideTransitionViews], completion: nil)

            }
            firstCardFlipped = true
        } else {
            //this works with no problem
            if matches[firstCard!] == title || matches[title] == firstCard {
                print("matched!")

                DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
                    UIView.transition(from: sender.imageView!, to: someView, duration: 0.3, options: [.transitionFlipFromRight, .showHideTransitionViews], completion: nil)
                }

                sender.removeFromSuperview()
                previousButton?.removeFromSuperview()
                previousButton = nil
                firstCardFlipped = false
                firstCard = ""
            } else {
                //this works but with problem :D
                guard let lastButton = previousButton else { return }
                print("Not matched!")
                print("\(lastButton.titleLabel?.text ?? "")  \(title)")

                firstCardFlipped = false
                firstCard = ""

                //flip the current card and flip back
                DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                    UIView.transition(from: sender.imageView!, to: someView, duration: 0.3, options: [.transitionFlipFromRight, .showHideTransitionViews], completion: nil)
                }

                DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
                    UIView.transition(from: someView, to: sender.imageView!, duration: 0.3, options: [.transitionFlipFromRight, .showHideTransitionViews], completion: nil)
                }
                //flip the previous card back to imageView(the biohazard thing...)
                DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
                    UIView.transition(from: lastButton.viewWithTag(1984)!, to: lastButton.imageView!, duration: 0.3, options: [.transitionFlipFromRight, .showHideTransitionViews], completion: nil)
                }
                print(previousButton?.titleLabel?.text)
                previousButton = nil

            }
        }
    }

https://gifyu.com/image/UkZ4

Solved it by pulling out the creation of the view from the button's action and placing it at the birthplace of the button...It wasn't smart putting it there :D