При нажатии на кнопку отобразить многоугольник в PictureBox

Sub DrawPolygonExample(ByVal e As PaintEventArgs)
Dim g As Graphics = e.Graphics
Dim pn As New Pen(Color.DarkSlateBlue, 3)
Dim pnRhomb As New Pen(Color.SlateBlue, 3)
Dim Pol As Point() = {New Point(80, 60), New Point(100, 60),
New Point(120, 20), New Point(140, 60), New Point(160, 60),
New Point(160, 80), New Point(200, 100), New Point(160, 120),
New Point(160, 140), New Point(140, 140), New Point(120, 180),
New Point(100, 140), New Point(80, 140), New Point(80, 120),
New Point(40, 100), New Point(80, 80)}
Dim Rhomb As Point() = {New Point(80, 100), New Point(120, 60), New Point(160, 100), New Point(120, 140)}
g.DrawPolygon(pn, Pol)
g.DrawPolygon(pnRhomb, Rhomb)
End Sub

Private shw As Integer = 0
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    shw += 1
    pctbox1.Invalidate()
End Sub
Private Sub pctbox1_Paint(sender As System.Object, e As System.Windows.Forms.PaintEventArgs) Handles pctbox1.Paint
    If shw = 0 Then Exit Sub
    DrawPolygonExample(e)
End Sub