Suppose you find yourself teetering on the edge of a building with a heavy physics book in your hand. As you are about to fall, you suddenly remember how physics can save you. What law did you remember

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )