Most of these images are dominated by interference patterns. You can only stretch a digital image so far before it starts to exhibit what would have been called grain in the film world, but are the actual pixels that reside in the digital file limited by the file resolution and the screen display resolution.
Overlapping layers of different pattern images develop what is called a moiré pattern. You can read all about the math of these patterns at the above link.
I am not quite sure at what point these artifacts began to appear, but was in awe of the results and went on to produce a few similar images.