If we use only harmonics of the form k+n*m, then the figure will always have m-fold rotational symmetry. (This is NOT obvious - but neither is it difficult to prove if you know the workings of complex numbers. Just accept it for now. Those with a deeper thirst for knowledge and access to a good library will find the explanation in the book Creating Symmetry.)
In addition, the program allows amplitudes to be modified interactively with later figures superimposing on top of earlier figures, building up an image that is part algorithmic and part created by the use of the computer mouse. (This means that the images are not algorithmically reproducible - at the end of the process I get one JPEG file and a cannot easily go back and regenerate in higher resolution, for example. Even when I remember the approximate sequence of actions that produced and image, I find it difficult to reproduce something that looks similar.)
A surprising variety of images can be generated from the same essentially simple program. Some people find the symmetry pleasing, others might find that the regularity is too strong. Perhaps they are easily enjoyed for a short time, but I am not sure how often one would wish to come back. It was an interesting and worthwhile learning exercise but I tend to prefer images that have a hidden, less obvious underlying order, rather that ones like this where it is "in your face".
