Fractals are geometrical patterns, based on mathematical formulas, that repeat themselves at ever smaller scales to produce irregular shapes and surfaces. If you zoom in on a part of it, the structure remains almost the same. For example: like a mountain that looks rocky from a distance; the rocks you find on the mountain may resemble the mountain themselves. The spiral, that repeats itself endlessly, is easy recognized as a fractal. The fact that fractals are made using mathematical formulas does not mean that fractals are not natural. On the contrary. Nice natural fractals are for instance ice crystals on frozen windows, or a capricious coastline. And a beautiful example of a fractal spiral is the vegetable Romanesco.