ThreadingEx02.cs

using System;
using System.Threading;
 
class Program
{
    static void Main(string[] args)
    {
        Thread t1 = new Thread(MyBackgroundTask);
        Thread t2 = new Thread(MyBackgroundTask);
        Thread t3 = new Thread(MyBackgroundTask);

        t1.Start("X");
        t2.Start("Y");
        t3.Start("Z");

        for (int i = 0; i < 500; i++)
        {
            Console.Write(".");
        }
    }

    static void MyBackgroundTask(object param)
    {
        for (int i = 0; i < 500; i++)
        {
            Console.Write(param);
        }
    }
}