In 1992 John Tippets published images based upon a variation of the then already famous Mandelbrot set. The Mandelbrot set is an image that describes how the series zn+1 = z2n + c behaves where the complex value c is taken to be each point on the complex plane making up the image. For more information see here. This is normalloy implemented as follows:
In Tippetts scheme the calculation is as follows. With all due respect to John Tippetts it is hard to imagine this didn't arise from a failed attempt at implementing the real Mandelbrot by a novice programmer.
The overall set is shown below. As with the classical shading of the Mandelbrot, the intensity is proportional to how quickly the series using point c on the plane escapes to infinity.