1 class Program

  2     {

  3         private static List<int> intlist;

  4         static void Main(string[] args)

  5         {

  6             intlist = new List<int>() {0};

  7             Task task1 = Task.Factory.StartNew(() => Part1());

  8             Task task2 = Task.Factory.StartNew(() => Part1());

  9             Task.WaitAll(new Task[]{task1, task2});

 10             Console.Read();

 11         }

 12

 13         private static void Part1()

 14         {

 15             lock (intlist) //

 16             {

 17                 for (int i = intlist[intlist.Count - 1]; i < 30; i++)

 18                 {

 19                     intlist.Add(i);

 20                     Thread.Sleep(300);

 21                     Console.WriteLine(i.ToString());

 22                 }

 23             }

 24         }

 25

 26     }

 27