The C4 model for visualising software architecture has been gaining traction, with many organisations adopting it as their preferred way to document software architecture. Although C4 is relatively lightweight and straightforward, there are several misconceptions that I see on a regular basis, and several common ways in which teams use C4 incorrectly. Join me for a tour of these things, and hear my advice on how to model things like shared code, microservices, and larger software systems.