What items could I put in a box that would represent the book "And Then There Were None"?

I have a big book project in school and I chose the book "And Then There Were None" by Agatha Christie. I have to do 6 different projects with the book, and one that I want to do requires me to make a "time capsule" of items that have reverence to the book, like a revolver or a judge wig. Does anyone know anything else I could put in it?