Building blocks approach to breaking down complex systems and concepts is one of the simplest yet powerful ways to navigate this complex world.
There are a few ways to think about blocks. Blocks can be a part of the system. The factor of split is that they form a component with a defined boundary. Another way to look at a block an abstract container for a feature. They may not have a specific physical significance. But they form an abstraction that is important in the context for the system.
Now moving onto connecting these blocks. A connection denotes a relationship. And relationships can have different meanings and also depends on which end of the relationship you are looking at. Hence a directional approach is required most times. Another way to connect blocks could be based on the temporal significance between the blocks. In other words, where blocks are arranged to form a sequence.