A fractal is a figure with a self-similar pattern. Usually the fractals are calculated with a computer, but is is possible to produce Fractals without a Computer! It’s very cool – partly because it looks neat, but also partly because it shows you something important about fractals.
Optical video feedback is a well-known phenomenon. If you hook a camera up to a TV and then point it at the TV, you get an infinite regression of images. I remember playing with this effect at 1980′s when first time playing with video camera. You can get some interesting effect in this way (was cool at that time, nothing spectacular at today’s standards when computer special effects are widely used in videos).
This video shows that you can use the same feedback phenomenon with multiple displays to make fractals.