My latest notebook I’ve made enlarges when you untie the ribbon from a 9cm square when folded to 18cm square. My husband says they make great revision books as you can slip it in your pocket or handbag. To make one, you need approximately 9 x 18cm squares, depending on how many pages you’d like. Each square is then folded in half both horizontally and then vertically. Turn the paper over and fold once horizontally. Each folded sheet needs to then be glued in position. Glue one little square onto another sheet’s 9cm square (which you turn over first so the sheets are alternated). Repeating this process produces a garland of squares and the forward and backward valley folds help to expand or fold up the book.