Рисуется пять окружностей вместо десяти - Visual Basic .NET

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim a As Integer
        Dim Graph As Graphics
        Dim P1 As Rectangle
        P1.X = 150
        P1.Y = 150
        P1.Width = 100
        P1.Height = 100
        a = 10
L1:     Graph = Me.CreateGraphics
        Graph.DrawEllipse(Pens.Black, P1)
        P1.Inflate(-10, -10)
        a = a - 1
        If a > 0 Then
            GoTo L1
        End If
    End Sub
End Class