If it has structure, it can be modular.
“Grids follow the same principle of modularity we’ve been considering the last few weeks. In some ways that seems obvious given the terminology modular grids. In other ways though it isn’t quite as obvious that they’re the same thing. However, when you think about how grids divide space and make it easier for us to make layout decisions, I think the modularity of grids falls right in line with the reusable modularity of components and design patterns. They separate concerns, by dividing the space into modular units. The characteristics of these modular units are reusable and through reuse help us more efficiently place information. Finally, the structure of these units in the grid leads to greater consistency in how content is organized.”