<Extension()> _
Public Function RoundRect(ByVal form As Form, _
                     Optional ByVal radius As Integer = 18) As Region
    form.FormBorderStyle = FormBorderStyle.None
    Return New Region(New Rectangle(0, 0, form.Width, form.Height).RoundRect(radius))
End Function
 
<Extension()> _
Public Function RoundRect(ByVal rect As Rectangle, ByVal radius As Integer) As Drawing2D.GraphicsPath
    Dim oPath As Drawing2D.GraphicsPath = New Drawing2D.GraphicsPath()