Legal rules as software

This article was written for the law school course 'Building Legal Apps' that I taught at The Colleges of Law (fall 2022).

Part 1: Intro

A review of the basic mechanics of building apps with PatternBuilder:

Understanding variables is essential to automating legal rules with PatternBuilder.

Let's imagine our app can only be used by people who are at least 21 years old. How do we automate this rule?