C# formun arka plan rengi nasıl ayarlanır?

this.BackColor = Color.FromArgb(255, 232, 232);

Random rnd = new Random();
 int num1;
 int num2;
 int num3;
 for (int i = 0; i < 100; i++)
 {
 num1 = rnd.Next(0, 255);
 num2 = rnd.Next(0, 255);
 num3 = rnd.Next(0, 255);
 this.BackColor = Color.FromArgb(num1, num2, num3);
 this.Refresh();
 Thread.Sleep(50);
 }

this.BackColor = Color.Blue;

private void Form1_Load(object sender, EventArgs e)
{
    Random rnd = new Random();
    this.BackColor = Color.FromArgb(rnd.Next(256), rnd.Next(256), rnd.Next(256));
}

Random rnd = new Random();

private void Form1_Load(object sender, EventArgs e)
{
    Timer timer = new Timer();
    timer.Interval = 1000;
    timer.Tick += new EventHandler(timer_Tick);
    timer.Start();
}

private void timer_Tick(object sender, EventArgs e)
{
    this.BackColor = Color.FromArgb(rnd.Next(256), rnd.Next(256), rnd.Next(256));
}