Dim al As New List(Of Form)
    Private Const wh As Integer = 60
    Private Const loops As Integer = 10
    Private dec As Integer = Math.Ceiling(wh / loops)
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Dim sb As Rectangle = Screen.GetWorkingArea(New Point(0, 0))
 
        Dim f1 As New Form2
        f1.Height = wh
        f1.Top = sb.Height - wh
        f1.Left = sb.Width - f1.Width
        f1.BackColor = Color.Red
        al.Add(f1)
        f1.Show()
 
        Dim f2 As New Form2
        f2.Height = wh
        f2.Top = f1.Top - wh
        f2.Left = f1.Left
        f2.BackColor = Color.Blue
        al.Add(f2)
        f2.Show()
 
        Dim f3 As New Form2
        f3.Height = wh
        f3.Top = f2.Top - wh
        f3.Left = f1.Left
        f3.BackColor = Color.Green
        al.Add(f3)
        f3.Show()
 
    End Sub
 
 
    Private Sub CollapseButton_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles CollapseButton.Click
        If al.Count = 0 Then Return
        Dim f As Form = al(0)
 
        For i As Integer = 0 To loops - 1
            f.Height -= dec
            For Each f1 As Form In al
                f1.Top += dec
            Next
            System.Threading.Thread.Sleep(100)
        Next
        f.Dispose()
        al.RemoveAt(0)
    End Sub

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