A number of papers deal with natural branching structures like lightning, stress cracks and rivers. These are so commonly experienced and intuitively that we use then to visualize properties of semantic tree structures.  

This comment collects a number of papers in this theme. One such paper is fascinating but possibly borderline science; it doesn’t matter for our purposes. The idea is that you can create small lightning bursts and capture them on film. The form of the lightning image, a Lichtenberg Figure, is determined by properties of the medium. This paper claims that the forms can be used to diagnose biological conditions. 

(More to come)

The Relationship to Kutachi

The Gudakova paper is a sort of sweet spot for us, though the science comes close to physic claims for Kirlian photography. They have gas flowing through a variable medium with the form of the gas discharge visually conveying basic properties of the form. This is similar to what we attempt.

Links

Broken Symmetry of Structure of Gas-Discharge Lichtenberg Figure when Biological Liquid is Placed into Electric Field. G Z Gudakova and I E Lublinskaya. 1989 [Symmetry of Structure]

The Kutachi essay on Fluid Flows. (not online yet)

The Kutachi essay on Lightning. (not online yet)