Which packaging innovation, first widely used in the 2010s, created a social media phenomenon where readers would share photos of the hidden artwork revealed when the book was displayed a certain way?

The publishing industry has seen numerous innovations in how books are packaged and presented to consumers. From dust jackets to foil stamping, deckled edges to sprayed edges, publishers have continuously experimented with ways to make physical books more appealing in an increasingly digital world. Test your knowledge about notable packaging innovations that have influenced book sales and collector interest in the publishing industry.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

Sprayed edges (where the edges of pages are painted with designs that are only visible when the book is closed)
Reversible dust jackets (where removing the cover reveals an alternate artwork underneath)
Transparent overlay covers (where a clear plastic cover with printed elements overlays the main cover art)
Die-cut covers (where strategic cutouts in the cover reveal portions of the page beneath)