Summary
That wasn't an easy chapter. It doesn't matter if the interconnection of all the various classes and interfaces doesn't make complete sense yet. Certainly, go back and re-read the Entity-Component pattern and the Simple Factory pattern sections along with studying the code so far. However, continuing with the project as we code more of the components to finish the game will also help just as much.
In addition, the next project starting in Chapter 22, Exploring More Patterns and Planning the Platformer Project will also help clarify the structure of the code. So, don't spend too long scratching your head if components and factories aren't completely clear- keep making progress because using the concepts will bring clarity much more quickly than thinking about them.
When planning the book, I thought about stopping after the Snake game but that wouldn't be fair because you would have been armed with just enough knowledge to start to implement a bigger game...
