A Universe Explodes is an unusual e-book in a variety of ways. Best viewed on a mobile device, it’s about 20 pages long and has 128 words per page. Only 100 people “own” the original version, though the book itself is free and can be read by anyone at any time. Each copy can be shared with up to 100 others, but first each owner must personalize it by removing two words and adding one to every page. Since each copy is subtly different, they are all considered “limited editions.” Owners are required to share the book with a friend once they’re done editing it — and each time the e-book is passed on, more and more words disappear until there’s only one left per page. READ MORE: This experimental e-book gets edited every time it changes hands | engadget