Fractals (in a very informal sense) are interesting images or shapes generated by a simple (but typically recursive) mathematical function.
One of the most familiar fractal images is the Mandelbrot set:
This image was generated with my web-based fractal explorer.
I first became interested in fractals in 1994, after reading about them in Encyclopaedia Britannica's Science and Technology Yearbook.
Here are some wallpapers:
