Graphics 640, 480, 0, 2

   Local img_bg = CreateImage(GraphicsWidth(), GraphicsHeight()), img_output = CreateImage(GraphicsWidth(), GraphicsHeight()), img_hf = CreateImage(200, 200)
   SetBuffer ImageBuffer(img_bg)
   For i = 0 To 999
      Color Rand(255), Rand(255), Rand(255)
      Rect Rand(GraphicsWidth()), Rand(GraphicsHeight()), Rand(50), Rand(50)
      Color Rand(255), Rand(255), Rand(255)
      Oval Rand(GraphicsWidth()), Rand(GraphicsHeight()), Rand(50), Rand(50)
   Next
   
   Repeat

      img_output = Hitzeflimmern(MouseX() - 100, MouseY() - 100, img_bg, img_hf, img_output)
      SetBuffer BackBuffer()
      DrawBlock img_output, 0, 0
      Flip()

   Until KeyDown(1)
   End


Function Hitzeflimmern(x, y, img_background, img_section, img_output, blocksize = 20, iterations = 50)

   Local w = ImageWidth(img_section), h = ImageHeight(img_section)


   SetBuffer ImageBuffer(img_output)
      Cls
      DrawBlock img_background, 0, 0   
      Color 255, 255, 255
      Rect x, y, w, h, 0


   Local s_x, s_y, s_h, s_w
   For i = 1 To iterations

      ;Nimm einen Ausschnitt aus Section
      s_h = Rand(h)
      s_y = y + s_h
      s_w = w / 2 + ((Float(s_h) / h) * Rand(w / 2)) * Sgn(Rand(-1, 1))
      s_x = x + s_w
      ;und blitte diesen Teil nach oben
      CopyRect s_x, s_y, blocksize, blocksize, s_x + Rand(-blocksize / 5, blocksize / 5), s_y - Rand(blocksize / 3, blocksize / 2), ImageBuffer(img_background), ImageBuffer(img_output)
   Next

   Return img_output

End Function