Question

The idea is that a single picture clearly illustrates what is otherwise kind of hard to
understand. For an example, look at this picture:
This illustrates the idea that a(a+b)=a^2+ab. Can you see how that works? Take a close look at the two different regions and how they are made.
Now take a look at this picture:
What does this picture illustrate? Make sure you show "both sides" of the equation, as shown in the example, and include some words (or a well-labeled
picture) to explain.