Here's our noun-verb diagram for Dead Static Drive's core gameplay loop:
Making a noun-verb diagram to explain at a glance "what could interact with what" was a huge turning point for us in terms of documentation (among other things!) and I thought I'd share it in case anyone found it useful. (I'll add a tip in the replies if you're going to give this a go)
I find this far more useful than a "bible" explaining all this over multiple pages before going in a drawer never to be read again.
We have copies of this laminated in the studio as well, and I like to draw on it with whiteboard marker and do little player scenarios to test things out before putting them in flowcharts and blueprints.
It's been useful for finding holes and questioning assumptions we were making about player motivations, and is super handy for pitching at a glance, people can understand the game so much faster with this than a bunch of bloated copy.