Voronoi noise with cyclic metrics, an experiment

While working on adding more functionality on voronoi nodes in OSL I was wondering if we could vary the metric in some interesting way. The result of one of those experiments is shown below:

The noodle used to generate this image looks like this:

Note the number 7 in de metric drop down.

Observations

The pattern looks decidedly different from other cell like patterns and depending on the value of E can be made to look like anything from x-ray diffraction pattern(? at E=28) to stylized models of atoms (E=2.6):

The code for this metric(*) is this:
length(d) + (1 + sin(e * length(d)))/2;
i.e. we basically add a sine component to the distance. If E is zero this metric reduces to a plain distance metric. (*) Note that this isn't a true metric in the mathematical sense as it does not satisfy the triangle inequality.

Code

The code is a minor adaptation of my previous script and is available on GitHub.

If you would like to know more about programming OSL you might be interested in my book "Open Shading Language for Blender". More on the availability of this book and a sample can be found on this page.