c# thread lock 명령어로 critical section 조절하기

==코드==

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
 
namespace ConsoleApp5
{
    class Program
    {        
        static void Main(string[] args)
        {
            LockThread lockthread = new LockThread();
            lockthread.Run();
        }
                
    }
    class LockThread
    {
        private int counter = 1000;
        private object obj = new object();
        public void Run()
        {
            for (int i = 0; i < 10; i++)
            {
                new Thread(LockCalc).Start();
            }
        }
 
        private void LockCalc()
        {
            lock (obj)                
            {
                this.counter++;
                for (int i = 0; i < this.counter; i++)
                    for (int j = 0; j < this.counter; j++)
                    {
 
                    }
                Thread.Sleep(1000);
                Console.WriteLine(this.counter);
            }
        }
    }
 
}