This generative art work is an elaboration of the strange attractor first described by Clifford A. Pickover in goodness who knows when? A long time ago, anyways.
A point jumps around the canvas 4,222,147,251 times according to two simple equations which give new X and Y co-ordinates depending on the old X and Y. The shade of grey of each pixel depends on how often it has been visited by the point on its journey.
This image is 4000 by 4000 pixels in PNG format.