The epithet pop-up is often applied to any three-dimensional or movable book, although properly the umbrella term movable book covers pop-ups, transformations, tunnel books, volvelles, flaps, pull-tabs, pop-outs, pull-downs, and more, each of which performs in a different manner. Also included, because they employ the same techniques, are three-dimensional. They made books more exciting and interactive, basically everything classic literature wasn't