" But didn't everyone have a shell? Hard, external armor protecting the soft, vulnerable creature beneath?
Perhaps, she thought, people were more like ammonites than one would suppose. Perhaps they too built shells on a consistent, unchanging factor- some quality or circumstance established in your youth. Each chamber in the shell just an enlargement of the previous. Growing year after year, until they spiraled around and locked themselves in place. "

― Tessa Dare , A Week to Be Wicked (Spindle Cove, #2)