We covered a lot of very large design concepts in a short period of time. We looked at a number of specific design patterns that help reduce the complexity of our code through reducing inter-object dependencies, commonly referred to as low coupling, and increasing the simplicity in which those objects work together, otherwise referred to as high cohesion.

We learned that there are three types of design patterns that focus on fixing different types of problems. Behavioral patterns help objects communicate with each other better, structural patterns facilitate the breaking down of complex structures into smaller and simpler ones, and creational patterns help with the initialization of new objects.

We also looked at some very specific features of Swift and how they can help us achieve similar goals to the ones we achieve with design patterns. We saw how to use enumerations with associated values to reduce the complexity of our type system and represent state in a better fashion; we used...