RE (2): Defer. The diagram has an extra box in the control flow which is unnecessary. You can label the big boxes from top to bottom like so: A E B <unnecessary

RE (2): Defer. The diagram has an extra box in the control flow which is unnecessary. You can label the big boxes from top to bottom like so: A E B <unnecessary> D C. A good use case for understanding the control flow of 'defer' is when cleaning up resources. mutex.lock(); defer { mutex.unlock(); } val f = File.open(filename); defer { f.close(); } // write to file It's a nice construct because it keeps construction and destruction close together instead of far apart mutex.lock(); val f = File.open(filename); // write to file f.close(); mutex.unlock();