Ever growing, ever changing. The nautilus shell consists of ever-larger chambers in which the sea creature lives for a while until it outgrows that particular chamber. Once it grows a new, larger chamber it cannot go back to the previous ones; they no longer fit. It has no choice but to move on. Yet, the old chambers are still a part of who they are. Your past defines who you are, you don't necessarily have to go back to your old ways but they are still apart of who you are today.