C# - ThreadStatic Attribut

using System;
using System.Threading;

class Program
{
    [ThreadStatic]
    static int a = 0;
    static int b = 0;

    static void Main(string[] args)
    {
        for (int i = 0; i < 10; ++i)
        {
            var t = new Thread(() =>
                {
                    for (int j = 0; j < 10; ++j)
                    {
                        ++a;
                        ++b;
                    }
                    Console.WriteLine("Thread #" + i + ":  {0,3} - {1,3}", a, b);
                });
            t.Start();
            t.Join();
        }
        Console.WriteLine("Mainthread: {0,3} - {1,3}", a, b);
        Console.ReadKey();
    }
}