Yeah I've got a notation that's kind of based on mind maps. I put 'standing stones' in the middle of a whiteboard to represent desired outcomes, and then try to create a path from the edge of the whiteboard into the stones.

It's useful to track where your dead ends are for further discussion. Someone else comes along and says "why didn't you just do this?" and you can't remember why, just that there was what seemed like a good reason at the time.