Not just patterns, full disassemblies of the game exists[1], so I imagine the locations in RAM where each particular piece of info is stored are known and can be tracked easily.

[1]: https://gist.github.com/1wErt3r/4048722

Hello, author here! Check this blogpost for an explanation =) http://coconauts.net/blog/2016/08/01/retrophies/