Some interesting interpretations of 300.20

[sdbob]

And some really SUPER creative ways to wire with romex that I'd never considered. https://www.reddit.com/r/askanelectrician/comments/xqt2dp
Learn something new every day, right? Wait... lemme look that up...

 

[Dennis Alwon]

There are many types of wiring for 3 way switches. This hookup looks like they used the neutral from another feed



There are many names and different hookups. Chicago 3 way, travelling bus 3 way some are different names for the same hookup.