There are more examples of masks being used in other assets that you might want to check out. This is something easy to do, as we've included Starter Content in this project, where we can find a couple of other materials that make use of the technique we've just seen.
You can find them in the following folder: Starter Content | Props | Materials. Shaders such as M_Door or M_Lamp have been created according to the methodology explained previously, so be sure to check them out!