Griffin and Sabine (Nick Bantock) is also somewhat similar. There the entirety of the story is cards and letters written between the title characters. It has

Griffin and Sabine (Nick Bantock) is also somewhat similar. There the entirety of the story is cards and letters written between the title characters. It has the same idea of having these as inserts within the book. It was well done; the "found object" nature of it has a nice quality.