Public Class frmBlink
 
 
    Dim WithEvents picturebox1 As New PictureBox With _
       {.Parent = Me, .Width = 300, .Height = 300}
 
    Dim WithEvents tim As New Timer With _
       {.Interval = 1000, .Enabled = True}
 
 
    Private Sub PictureBox1_Paint(ByVal sender As System.Object, ByVal e As  _
      System.Windows.Forms.PaintEventArgs) Handles picturebox1.Paint
        Dim g As Graphics = e.Graphics
 
        Static isvisible As Boolean = False
        If isvisible Then
            g.FillEllipse(Brushes.Black, New Rectangle(10, 10, 100, 100))
        End If
        isvisible = Not isvisible
    End Sub
 
 
    Private Sub tim_Tick(sender As Object, _
        e As System.EventArgs) Handles tim.Tick
 
        picturebox1.Invalidate()
 
    End Sub
 
End Class