public Form1()
{
    InitializeComponent();
    this.DoubleBuffered = true;
    shapes.Add(new Rect() { Location = new Point(100, 100), Size = new Size(50, 30) });
    shapes.Add(new Rect() { Location = new Point(220, 200), Size = new Size(20, 40) });

    Random random = new Random();
    timer.Tick += delegate
    {
        foreach (Shape shape in this.shapes)
        {
            shape.RotateAngle += random.Next(10);
            this.Invalidate();
        }
    };
}

System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer() { Enabled = true, Interval = 100 };
List<Shape> shapes = new List<Shape>();
protected override void OnPaint(PaintEventArgs e)
{
    foreach (Shape shape in shapes)
    {
        e.Graphics.TranslateTransform(shape.Location.X, shape.Location.Y);
        shape.DrawTo(e.Graphics);
        e.Graphics.ResetTransform();
    }
}

public abstract class Shape
{
    public abstract void  DrawTo(Graphics g);
    public float RotateAngle { get; set; }
    public Point Location { get; set; }
}

public class Rect : Shape
{
    public Size Size { get; set; }
    public override void DrawTo(Graphics g)
    {
        PointF center = new PointF(Size.Width / 2.0f, Size.Height / 2.0f);
        g.TranslateTransform(center.X, center.Y);    //<--1
        g.RotateTransform(RotateAngle);              //<--2
        g.TranslateTransform(-center.X, -center.Y);  //<--3

        g.FillRectangle(Brushes.PeachPuff, new Rectangle(Point.Empty, Size));
    } 
}