Note: I would have done this as a Quick Take, but it doesn't allow images.
In the spirit of How I got 4.2M YouTube views without making a single video, I improved a diagram on the wikipedia page for Pareto Efficiency.
ORIGINAL VERSION
NEW VERSION
Based on the text, I don't think the author understood that Cooperate/Cooperate isn't the only Pareto efficient outcome ("Thus Both Cooperate is Pareto-efficient"). It's a small change and I think the text is more in need of improving, but this is all I can do now.