Fold paper in half lengthwise.
Then fold the width in half three times.
You will have a long, fat package.
Unfold the paper completely and cut the two slits according to the diagram.
Correct all Mountain folds and Valley folds accordingly.
Fold the paper in half lengthwise along the original long fold.
The X's indicate folds that must be flattened with a bone folder.
Pull below the cuts into Mountains and above the cuts push into Valleys .
You will have a two page, pop-out booklet.
These can be duplicated and sewn or glued together to make a multi-page book.
Further pop-up cuts can be made on the short Mountain folds.

If you have questions about this structure,
contact Patrice Baldwin patbooks@mindspring.com