I read this answer <https://stackoverflow.com/a/833124/5175709> and some other questions. From what I understand it's that since the object could expand and run out of space then the memory location my also change. I never understood why we shouldn't use `**` for `NSMutableData` or `NSMutableArray` since they could also expand with any `add`ing or `append`ing and be in need of more space.

Please correct me where I understood wrong. I am confused.