                            UIButton(),  // top right
                            UIButton(),  // bottom left
                            UIButton()]  // bottom right
+    private let precisionView = UIView()    // view containing lines
 
     private var cornerButtonWidth: CGFloat = 45
 

                $0.heightAnchor.constraint(equalToConstant: cornerLineLength).isActive = true

                if index <= 3 {
                    $0.topAnchor.constraint(equalTo: topAnchor, constant: outterGap).isActive = true
                } else {
                    $0.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -outterGap).isActive = true
                }

                if index % 4 == 0 {
                    $0.leftAnchor.constraint(equalTo: leftAnchor, constant: outterGap).isActive = true
                } else {
                    $0.rightAnchor.constraint(equalTo: rightAnchor, constant: -outterGap).isActive = true
                }
            } else {
                $0.widthAnchor.constraint(equalToConstant: cornerLineLength).isActive = true
                $0.heightAnchor.constraint(equalToConstant: cornerLineDepth).isActive = true

                if index <= 3 {
                    $0.leftAnchor.constraint(equalTo: leftAnchor, constant: outterGap).isActive = true
                } else {
                    $0.rightAnchor.constraint(equalTo: rightAnchor, constant: -outterGap).isActive = true
                }

                if index % 4 == 1 {
                    $0.topAnchor.constraint(equalTo: topAnchor, constant: outterGap).isActive = true
                } else {
                    $0.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -outterGap).isActive = true
                }
            }
        }
    }

    @objc func move(gestureRecognizer: UIPanGestureRecognizer) {

        buttons[3].heightAnchor.constraint(equalTo: buttons[3].widthAnchor).isActive = true
    }

    private func loadPrecisionView() {
        precisionView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(precisionView)

        precisionView.isUserInteractionEnabled = false
        precisionView.layer.borderWidth = 1
        precisionView.layer.borderColor = UIColor.white.cgColor

        precisionView.topAnchor.constraint(equalTo: topAnchor, constant: outterGap).isActive = true
        precisionView.leftAnchor.constraint(equalTo: leftAnchor, constant: outterGap).isActive = true
        precisionView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -outterGap).isActive = true
        precisionView.rightAnchor.constraint(equalTo: rightAnchor, constant: -outterGap).isActive = true

        loadCornerLines()
        loadPrecisionLines()
    }

    private func loadCornerLines() {
        let cornerLines = [UIView(), UIView(),  // top left
            UIView(), UIView(),  // top right
            UIView(), UIView(),  // bottom left
            UIView(), UIView()]  // bottom right

        cornerLines.forEach {
            $0.translatesAutoresizingMaskIntoConstraints = false
            precisionView.addSubview($0)

            $0.isUserInteractionEnabled = false
            $0.backgroundColor = .white
