Public Class frmLinesAnimation
 
    Dim WithEvents pl As New Panel With _
       {.Parent = Me, .BackColor = Color.Yellow}
 
    Dim WithEvents anitim As New Timer With {.Interval = 100}
 
 
    Private Sub frmLinesAnimation_Load(sender As Object, _
        e As EventArgs) Handles MyBase.Load
 
        Me.MinimumSize = New Size(300, 300)
        diff = 1
        t = pl.Height \ 2
        anitim.Enabled = True
    End Sub
 
 
    Private Sub frmLinesAnimation_Resize(sender As Object, _
        e As EventArgs) Handles Me.Resize
 
        pl.Top = 50
        pl.Left = 50
        pl.Width = Me.ClientRectangle.Width - 100
        pl.Height = Me.ClientRectangle.Height - 100
    End Sub
 
 
    Dim t, b, diff As Integer 'Y-Position der Linien und Bewegungsrichtung
 
    Private Sub anitim_Tick(sender As Object, e As EventArgs) Handles _
      anitim.Tick
 
 
        If diff = 1 Then
            If t < pl.Height \ 2 Then t += diff Else diff = -1
        ElseIf diff = -1 Then
            If t > 1 Then t += diff Else diff = 1
        End If
 
        b = pl.Height - t
 
        pl.Invalidate()
 
    End Sub
 
 
    Private Sub pl_Paint(sender As Object, e As PaintEventArgs) Handles pl.Paint
        Using p As New Pen(Color.Red)
            e.Graphics.DrawLine(p, 0, t, pl.Width, t)
            e.Graphics.DrawLine(p, 0, b, pl.Width, b)
        End Using
    End Sub
End Class