Unspoken agreement

When spoken—

You can freely take what you need of mine as long as I can freely take what I need of yours

So if you need to read my writing, you can do that as long as (in the same breath) you agree to allow me to take/use/license anything you create or supply (or own)

If you're a grocer, you reading my writing for free means I can freely take what groceries I need from you—if you don't allow me to take what I need of your groceries for free, you can't read my writing for free

If I'm a grocer, and you're a movie producer, you are allowed to feed yourself for free from my groceries as long as I am allowed to watch your movies for free

If you're a movie producer, and you want to make a movie based on one of my books, feel free to do that with any of my books as long as I can watch any of your movies for free

What is yours and what is mine is defined as widely as possible—there is no distinction between what I own and what I produce and what I control. If you need my hat, you can take my hat freely as long as I can take from you freely as I need

Need is defined by the person doing the taking—that is the person/entity best suited to determine their own need

Free is defined as a permanent downstream quality—if I give you something for free, you can't then charge others for your products based upon that thing (you can't resell my writing or movies based upon my writing—and I can't sell groceries I got from you for free)

This is the unspoken agreement