olemus
prindivorming, tekitab
lehekülgeteks volditava raamatupoogna
=
a page-folding print format used in the book production

https://en.wikipedia.org/wiki/Book_folding

näiteid
https://1.bp.blogspot.com/_YDLqzir7jCQ/RYSgG7yhJmI/AAAAAAAAAAw/-SsQFZaCd5s/s320/Folding-Paper-Sheets.jpg