The Mandelbrot set is the set of all complex numbers that satisfy a particular computational requirement. The equations are explained in the Mandelbrot Set Wikipedia article. I have adopted the Mandelbrot set as my logo.
On the web there are many pages showing the beauty of the set as it is calculated with higher and higher resolution. I like the following images of the whole Mandelbrot set at larger scales.
With the ability to record slide shows, there are also Mandelbrot zooms, which give the impression of diving into the set as it calculated with increasing resolution. My favourite Mandelbrot set zoom video is on YouTube. It shows how as you expand the set, the same images recur at smaller and smaller levels of details, which is one of the defining characteristics of fractals. No matter how much you expand the set, you never get a simple sharp edge; it is always fuzzy. If you can make yourself listen to the soundtrack, it also explains the Mandelbrot set quite well.
If you want to learn more about fractals, I recommend two books.
I read the first edition of this book in the late 1980s. It explains in a very readable way the difference between chaotic systems (which are theoretically predictable and governed by deterministic equations) and randomness. The weather is theoretically completely predictable, but small differences and measurement errors multiply up over time. Hence the saying about a butterfly flapping its wings in China leading to a typhoon elsewhere.
This is Mandelbrot's original masterpiece. It is very well written, but is quite a challenging book to read. I would not recommend it unless you have studied mathematics to at least UK GCE A Level, and preferably first year undegraduate level.
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