Here is where we talk about the other half of the process. How do numbers match up to particular locations, first on the computer screen, and then in the image file, and finally in the print-out?

The Cartesian coordinate system, familiar from high-school analytical geometry, not to mention calculus, is built into the computer's hardware and software. To use it is simple and straightforward. To use any other method requires work.

There are many other time-honored ways of associating numbers and formulas, on the one hand, and geometric constructions, on the other. Most of us are familiar with polar coordinates.

My most fruitful forays into exotic image geometry have involved hierarchical systems of labeling. Typical hierarchical systems involve squares within squares, many of which I have used with pleasure. But my favorite of all is GBT, which in two dimensions involves rosettes of regular hexagons.

"Greep" is my word for a toolbox of algorithms that I use for selecting colors when objects other than numbers are to be analyzed. All of my GBT images involve greeps.