Why does Xcode Playground execute liveView through iPad-like Simulator?

Question

I'm trying some codes in Xcode 8.2.1 Playground with Swift 3.
I've been confused since PlaygroundPage.current.liveView executes iPad-like simulator.
I want to test keyboard input through a simulator of smaller device. Can I handle this better?

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        setupTextView()
    }

    private func setupTextView() {
        let textView = UITextView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height))
        textView.backgroundColor = .gray
        textView.isSelectable = true
        textView.font = textView.font?.withSize(20)
        view.addSubview(textView)
    }

}

let viewController = ViewController()
let window = UIWindow(frame: CGRect(x: 0, y: 0, width: 640, height: 600))
window.rootViewController = viewController
window.makeKeyAndVisible()

import PlaygroundSupport

PlaygroundPage.current.liveView = window
PlaygroundPage.current.needsIndefiniteExecution = true

Answer 1

Instead of

let viewController = ViewController()
let window = UIWindow(frame: CGRect(x: 0, y: 0, width: 640, height: 600))
window.rootViewController = viewController
window.makeKeyAndVisible()

import PlaygroundSupport

PlaygroundPage.current.liveView = window
PlaygroundPage.current.needsIndefiniteExecution = true

Try this

let viewController = ViewController()
viewController.preferredContentSize = CGSize(width: 640, height: 600)

import PlaygroundSupport

PlaygroundPage.current.liveView = viewController
PlaygroundPage.current.needsIndefiniteExecution = true

This is how I change the size of my view controllers in Playgrounds