# Hillel Wayne - Behaviors :: Learn TLA+ (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article0.00998d930354.png) ## Highlights - a spec only passes if every behavior passes - Either - The important thing is that TLC will run *every* branch. When it encounters an either, it creates a separate behavior and executes a different branch for each one. - it creates a behavior for each element in the set. like variables