create a program that starts two new threads, and then 2 more threads inside those threads in csharp

main.cs
using System;
using System.Threading;

class Program
{
    static void Main()
    {
        // Create the first two threads
        Thread t1 = new Thread(() =>
        {
            Console.WriteLine("Thread 1 started");
            Thread t3 = new Thread(() =>
            {
                Console.WriteLine("Thread 3 started");
            });
            t3.Start();
        });

        Thread t2 = new Thread(() =>
        {
            Console.WriteLine("Thread 2 started");
            Thread t4 = new Thread(() =>
            {
                Console.WriteLine("Thread 4 started");
            });
            t4.Start();
        });

        // Start the first two threads
        t1.Start();
        t2.Start();

        Console.ReadLine();
    }
}
762 chars
36 lines

main.cs
Thread 1 started
Thread 2 started
Thread 3 started
Thread 4 started
68 chars
5 lines