ViewController.swift

import UIKit

class ViewController: UIViewController {
    
    private lazy var view1: UIView = {
        let view = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
        view.backgroundColor = .blue
        return view
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        view.addSubview(view1)
    }
}