This book is a modified Size 5 book that has had the sides cut down to create an equilateral triangle for the cover.
So the spine of the book is a full eleven inches (10.5 for the block) and the width at the middle is nine inches (8.5 for the block).
The book was done for a client out of Norway who wanted an 'unusual book' with a triquetra recessed into the cover. This is actually the second of two triangle books that I did. This version had no closures (at the client's request) and the second had no cover design but two snap closures located midway along the two angled sides.
The second book was given to the prop company who did the work for Stargate: SG1. There was a call on one of my bookbinder forums where the prop company needed a 'bunch' of handmade books but did not have the budget to buy them from a prop maker. So the head prop guy put the word out that he would accept any donations and send all of the binders back a letter of acceptance and appreciation. Basically it was a way for binding geeks who were also into SCI-FI to get their hobby on film.
So I thought that a triangular book would catch their attention. Sure enough - if you look real carefully in the background of Episode 11, Season 3 (Past and Present) where you see a pile of books and notebooks you'll see the triangular edge of my book. Granted you have to be looking for it but when I saw it I gave a not-so-silent Whoot-Whoot!
So to show off what the inside of the book would look like if you used it for actually writing, a good friend of mine took one of the blank pages I had cut out but did not use and threw in some basic illustration and text to show off the alignment.