Underlying Graphics Arts Model
The model underlying many of my graphics art programs is based upon the over sampling of a functional contour map. To make this concept clear, consider a function of x and y that generates a hill shape:

Underlying Model

If this function is plotted on a three dimensional graph, it generates an image like

Plot of Underlying Model

If one wanted a quick and dirty contour plot of this function, one could try a two dimensional plot where various values were represented by different colors:

Simple Contour map

Note that each successive color ring represents a diffent range of function values.

In the three animated demonstration plots, the results of increasing the number of rings while keeping the number of colors constant are show.
First Demo
Demo 1   In this first demo, the number of colors is 16 and the number of rings varies from 4 to 32. Notice that beyond 16 rings, the colors repeat themselves. The rings have the appearance of simple rings whose width indicates the steepness of the curve.
Second Demo
Demo 2   In this demo, the number of rings range from 4 thru 96, in steps of 4. As with the first demo, the lower ring counts yield sets of narrow, concentric rings that at first appear approximately smoothly circular. However, as the ring count approaches the 72-76 range, anomalies begin to appear that introduce non-circular structure into the rings.
Third Demo
Demo 3   As the increasing ring count yields massively oversampled images, this anomalous structure gets more pronouced with pronounced radial elements (e.g., fish-shaped creatures). By varying the parameters of the generation process (e.g., number of colors, number of rings, and formula weights) various interesting families of images can be generated.