I could be mildly violating both of these, but I’m not sure. These two books are ergodic works (i.e., similar to the OP, many orders of reading are available, though certainly not AS many)
S., written by JJ Abrams and Doug Dorst, is a book about a book - The Ship of Theseus - that has an epistolary dialogue scribbled in the margins, a code wheel, and lots of physical artifacts (postcards, receipts, etc.). I think that would fully satisfy the OP. I was halfway through when I got distracted and stopped, but I should go back to it.
House of Leaves, by Mark Z. Danielewsi, the original version of which has a cover .25 inches shorter than the book (this is meaningful), and which has color coding, reversed text insets, and other strange things. Also, more footnotes than David Foster Wallace (and to a significant extent making fun of that). I quite enjoyed this one, and will reread it soon; it has its own subreddit of investigations into its nooks and crannies.
Griffin and Sabine was something of a hit in the '90s. It’s a novel made of the correspondence between a British man and a woman in the south Pacific. When they exchange postcards, you see the face of the postcard on one page and the back of it with their missive written on it on the other side of the page. When they write letters, there’s an envelope stuck to the page with a physical document inside that you can take out and unfold to read. It gets kinda weird toward the end.
The 1969 French novel La Disparition was written without using the letter E. The English translation A Void follows the same constraint, and many other translations have similar ones; the Spanish edition has no A and the Russian has no O.
I remember a fad for at first children’s books and then some for adults with pages separated into, usually, three horizontal pieces on a ring-like binder. Flipping the pieces created drawings or texts that stayed meaningful no matter how different the number of pages flipped over.
What I don’t remember is what the genre was called. I found a brand name of flip-and-flop books from Abbeville Press, with an example here.
I have a book on electric motor wiring and repair that has two spiral bound spines, so that pages bound on the left can be opened to show a certain type of motor, then other pages bound on the right can be opened to show different ways of wiring it. The last page of heavy board stock is also the rear cover with an index of sorts on the inside, and is the only page bound on both sides. It’s a neat idea, and fun to use, but remarkably hard to shelve properly…
Phillips drew, painted, and collaged over the pages, while leaving some of the original text to show through in the form of erasure. Through this process, A Humument is a new story with a new protagonist named Bill Toge, whose name appears only when the word “together” or “altogether” appears in Mallock’s original text.
Basically, a satirical look at the sex genre that was coming into vogue in the late 1960s, by the likes of Harold Robbins and Jacqueline Susann. “Penelope Ashe” was a pseudonym for 24 authors recruited by a Newsday columnist, and they were instructed to make their contribution as terrible as possible. Although I’ve never read it front-to-back, I’ve read excerpts, and yes, they’re full of sex and they’re pretty terrible. As a satire of the drugstore paperbacks from those days, it works.
I suppose Cloud Atlas has an unusual enough format to qualify. It’s six short stories set in different time periods with the protagonist of each section being a reincarnation of the same soul, which are nested within each other like a Russian doll. Halfway through the first story, it cuts off literally mid-sentence and the second story starts, and it’s about the person who’s reading the first story. This continues with the second, third, fourth, and fifth stories each cutting off halfway and jumping to the next protagonist in a later time period, starting in the mid-19th century and ending about a hundred years after a slow-motion environmental catastrophe in the 22nd century caused the collapse of civilization, mass death, and the survivors reverting to a primitive state. That story is presented uninterrupted, and is then followed by the second halves of the other five stories in reverse order, so that the novel concludes with the ending of the first story.
The movie doesn’t strictly adhere to the nesting format but does jump back and forth between the stories and time periods, and uses an interesting conceit - each of the actors playing one of the six protagonists also plays a supporting role in the other five stories.
There’s also The Heart of A Humument, which is the same strategy but using only the middles of the pages.
Tree of Codes cuts out sections of another novel to make a new novel.
Blackouts is a cut-up/excerpt/redaction novel.
Nox is a box containing a single long folded sheet of paper containing multiple media.
Cain’s Jawbone is a mystery that requires the book to be cut up to find the solution.
Extremely Loud & Incredibly Close plays a bit with typography and photos, including a sequence that pretty much functions as a flip book.
The True Meaning of Smekday includes a cartoon sequence, IIRC.
Kathy Acker used cut-ups and plagiarized text.
The Brief Wondrous Life of Oscar Wao, Jonathan Strange and Mr. Norrell, and Pale Fire all play with textual conventions such as footnotes and endnotes, and the latter has an index that plays word golf.
Hopscotch is another book that can be read straight through or jumped around in.
Alphabetical Africa subtracts then re-adds letters. Similarly, Ella Minnow Pea plays with pangrams. Heroin from A to Z is presented as short encyclopedia-style entries. Dictionary Stories is similar in some ways.
ETA: The Selected Works of T. S. Spivet plays with form/images, and Sunnybrook: A True Story with Lies presents an illustated narrative with marginalia pointing out where the author has fictionalized her autobiography.
The whole book is just that one number and it is a big book with small print. No real reason for it. No one will ever read it. But it is cool. 41,024,320 digits…that’s the whole thing. On my bookshelf behind me. Love it.
I also own an India Paper edition of the Lord of the Rings. The paper is unusually thin so the whole Lord of the Rings, in one volume, is the size of a normal book.
