Adding views in other views and checking which view is contained in what UIView

UIViewBasics.swift

func basicsOfViews() {
        let v = UIView(frame: CGRect(x: 100, y: 100, width: 150, height: 150))
        v.backgroundColor = .red
        self.view.addSubview(v)
        v.layer.masksToBounds = true
        
        let v2 = UIView(frame: CGRect(x: 130, y: 140, width: 150, height: 150))
        v2.backgroundColor = .yellow
        self.view.addSubview(v2)
        
        
        let v3 = UIView(frame: CGRect(x: 10, y: 10, width: 250, height: 250))
        v3.backgroundColor = .green
        v3.tag = 101
        v2.addSubview(v3)
        // This won't allow the subviews to leak out of the super view.
        v2.clipsToBounds = true
        
        print(v2.isDescendant(of: view))
        print(v3.isDescendant(of: v2))
        print(v3.isDescendant(of: view))
        print(v2.isDescendant(of: view))
        print(v.isDescendant(of: view))
        
        // Find the View by its Tag.
        let v101 = v3.viewWithTag(101)
    }