Connecting concepts: breaking up stuff into parts and indirection

I noticed a connection between two ideas: (1) breaking up a project into parts and (2) indirection.

One way to deal with complex projects is to break it up into subprojects. Each subproject is simpler and easier to deal with than the parent project.

This process can be done with the subprojects too. So each subproject can be a parent project to many child projects. Each child project is easier to deal with than its parent project.

Indirection means redirecting your efforts to child projects because their parent project is too hard (for you given your current skill) to deal with as one non-broken-up project.

Avoiding indirection means avoiding breaking up complex projects into simpler subprojects.