Public Class Form1
    Private Structure meinFenster
        Public Fenster As Form
    End Structure
    Private meineFenster As New List(Of meinFenster)
 
    Private WithEvents zeit As New Timer
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Dim f As Form = New Form
        Dim f1 As meinFenster
        'me hinzufügen
        f1.Fenster = Me
        meineFenster.Add(f1)
        'eine andere form hinzufügen
        f.Text = "TestForm"
        f.Show()
        'ein anderes fenster hinzufügen
        f1.Fenster = f
        meineFenster.Add(f1)
        'timer starten
        zeit.Interval = 1000
        zeit.Start()
    End Sub
 
    Private Sub zeit_tick(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles zeit.Tick
        Static number As Integer = 0
        Dim f As Form = meineFenster(number).Fenster
        f.TopMost = True
        number += 1
        If number > meineFenster.Count - 1 Then
            number = 0
        End If
    End Sub
End Class