To view the Viewcontroller child views as Live using Playground support. People who want to learn Visual Format Language(VFL) and try out how it look like. This will save lot of developer Time

InputScenePreview.Swift

//: Playground - noun: a place where people can play

import UIKit
import PlaygroundSupport

class InputScene : UIViewController {
    
    var emailTxtField:UITextField?
    var passwordTxtField:UITextField?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = .white
        self.emailTxtField = UITextField.init(frame: CGRect(x:0,y:0,width:320,height:70))
        self.emailTxtField?.placeholder = "Email address"
        self.emailTxtField?.addTarget(self, action: #selector(textFieldChanged), for: UIControlEvents.valueChanged)
        self.view.addSubview(self.emailTxtField!)
        
        self.passwordTxtField = UITextField.init(frame: CGRect(x:0,y:80,width:320,height:50))
        self.passwordTxtField?.text = "Password"
        self.passwordTxtField?.addTarget(self, action: #selector(textFieldChanged), for: UIControlEvents.valueChanged)
        self.view.addSubview(self.passwordTxtField!)
    }
    
    //MARK:- Selectors
    func textFieldChanged(sender:AnyObject) {}
}

PlaygroundPage.current.liveView = InputScene()