The development engine
Don't over-think this little picture, okay, but when I'm working with teams which are new to agile, or new to me, then I like to draw them some version of this picture.
It's a picture of the development machine and, depending on your own setup you can add different roles to the diagram as suits.
The three rules are:
1. Don't put poor quality fuel in the fuel tank - it'll just cause rework and it'll lose you productivity.
2. Try really hard to not run out of fuel
3. If you do run out of fuel, improve your system, but don't just keep people inside the engine room busy by feeding them low-value fuel.
You might draw your machine differently and you might have different rules. My intention is to show people how to think with a TOC mindset without needing to know TOC.