3D Box

private void Form1_Load(object sender, EventArgs e)
        {
            SolidBrush sb = new SolidBrush(Color.Black);
            Bitmap bi = new Bitmap(Width, Height);
            Graphics g = Graphics.FromImage(bi);
            Rectangle r = new Rectangle(20, 20, 150, 130);
            sb.Color = Color.Red;
            g.FillRectangle(sb, r);
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            sb.Color = Color.Black;
            g.DrawRectangle(new Pen(sb), r);
            Rectangle r1 = new Rectangle(40, 40, 150, 130);
            sb.Color = Color.FromArgb(150, 255, 255, 0);
            g.FillRectangle(sb, r1);
            sb.Color = Color.Black;
            g.DrawRectangle(new Pen(sb), r1);
            g.DrawLine(new Pen(sb), 20, 20, 40, 40);
            g.DrawLine(new Pen(sb), 170, 20, 190, 40);
            g.DrawLine(new Pen(sb), 20, 150, 40, 170);
            g.DrawLine(new Pen(sb), 170, 150, 190, 170);
            this.BackgroundImage = bi;

        }