c# - Task again

using System;
using System.Threading.Tasks;

namespace TestTask
{
    class Program
    {
        static void Main(string[] args)
        {
            T1();

            T2().Wait();

            T3().Wait();
            Console.WriteLine("T3 end");

            T4();

            while(true)
            {
                Task.Delay(1000).Wait();
                Console.WriteLine("Main() working...");
            }
        }

        public static Task T3()
        {
            Console.WriteLine("T3 start");
            return Task.Delay(1000 * 3);
        }

        public static void T4()
        {
            Console.WriteLine("T4 start");
            Task.Delay(1000 * 3);
            Console.WriteLine("T4 end");
        }

        public static async void T1()
        {
            Console.WriteLine("T1 start");
            await Task.Delay(1000 * 2);
            Console.WriteLine("T1 end");
        }

        public static async Task T2()
        {
            Console.WriteLine("T2 start");
            await Task.Delay(1000 * 3);
            Console.WriteLine("T2 end");
        }
    }
}