Good visual design is built on rules. Even if we don’t know what the rules are, or can’t describe them with words.
This book has told you to learn those rules, however you can. But not all of the rules were created equal.
Some of the rules already existed, and were discovered. They’re hard rules that exist because of the way our eyes and brains work.
And some of the rules were invented by designers. Maybe a thousand years ago. Maybe ten. These rules are softer. They’re guidelines. Useful, but not absolute.
You can ignore these rules if you understand them. You need to know why they exist. Where they came from. Their advantages. Importantly, their disadvantages.
If you know why Chesterton’s fence is there, you can tear it down.
If you want to make your mark on visual design, do it with confident knowledge of the rules you have ignored.