this is simple just fire on groupbox_Paint Event
private void groupBox1_Paint(object sender, PaintEventArgs e)
{
Graphics gfx = e.Graphics;
Pen p = new Pen(Color.Orange, 3);
gfx.DrawLine(p, 0, 5, 0, e.ClipRectangle.Height - 2);
gfx.DrawLine(p, 0, 5, 10, 5);
gfx.DrawLine(p, 62, 5, e.ClipRectangle.Width - 2, 5);
gfx.DrawLine(p, e.ClipRectangle.Width - 2, 5, e.ClipRectangle.Width - 2, e.ClipRectangle.Height - 2);
gfx.DrawLine(p, e.ClipRectangle.Width - 2, e.ClipRectangle.Height - 2, 0, e.ClipRectangle.Height - 2);
}