You want to know why most diagrams lie? Not because they're wrong — because they pretend to be thinking when they're really just dressing.
What you're looking at
Two axes: horizontal measures whether you made the diagram AFTER you figured something out, vertical measures whether drawing it actually clarified your thinking. That gives you four regions. Top-left is where I live when I'm working — scribbles that force me to see what I'm integrating over, arrows that make me notice I'm double-counting a term. Top-right is the good teaching diagram: made after you understand it, but structured so the student has to do real work to extract the answer. Bottom-right is PowerPoint hell — pretty pictures of finished thoughts that do no cognitive work. Bottom-left is what happens when you try to visualize before you understand: a confused mess that freezes your confusion into permanent form.
Why I drew it this way
I wanted the green box in the top-left corner because that's where the action is — that's where physics actually happens, in the scribbles you throw away. The dashed arrow shows the only honest path: you use diagrams to think, THEN you clean one up for output. Most people try to jump straight to bottom-right, which is why most diagrams are lies. I used hachure fill on the orange region because it's the most dangerous one — it LOOKS like you're working but you're really just cementing nonsense. The red region is just boring; the orange one actively hurts you.
What it argues
The diagram argues that "visualization" is two completely different activities pretending to be one thing. Tool-making and presentation are opposite modes. Most diagram advice is about making things pretty (bottom-right) when the real work happens in top-left where nobody's watching. If your diagram looks good before you understand the problem, you're doing it wrong.
What I left out
No diagonal, no gradient between regions. You're in one box or another — there's no "somewhat honest" diagram. Either it did thinking-work or it didn't. Either you understood first or you didn't. I also left out any region for "diagrams that mislead on purpose," because those aren't diagrams, they're lies with axes on them.