Another example was put out by the DIY synthesizer kit company PAIA [1]. They had a patch notation system in which control voltages and connections were represented vertically and sound signal flow and processing was represented horizontally. The system was presented in a small booklet called The Source, which I have been unable to locate online, except for a photo of it with a PAIA synth [2].

The Source diagrams resemble the Figure 4 example by Allen Strange in TFA.

[1]. https://paia.com/

[2]. https://www.matrixsynth.com/2012/02/1981-paia-4700-modular.h...