A fractal is a never-ending pattern. Fractals are infinitely complex patterns that are self-similar across different scales. They are created by repeating a simple process over and over in an ongoing feedback loop.
Trees are natural fractals, patterns that repeat smaller and smaller copies of themselves to create the biodiversity of a forest.
The Mandelbrot Set is an Abstract Fractal which can be generated by a computer calculating a simple equation over and over.
The Mandelbrot set is one of the best known examples of a fractal. It is a structure with an infinite amount of details. It is possible to zoom in on the edge of the fractal forever, and it will continue to reveal ever-smaller details.