To celebrate the long-awaited release of our new Smashing Book (yaaaay!), we’ve prepared a little mystery for you. Below you’ll find an animated GIF that contains a hidden message. Once you resolved the mystery, you’ll see a Twitter hashtag displayed in plain text.
Are you ready? Action! (Hint: watch out for the file name).

A hint: watch out for the file name.
Among the first readers who tweet us with the hashtag we’ll raffle a quite extraordinary, smashing prize (and a couple of other Smashing extras):
Please notice that to avoid spoilers, comments are closed for this post. The mystery will be revealed on a separate page this Thursday, November 28th, at 2pm CET. And sorry, we aren’t going to make it too easy for you. Alright. Let’s get to work. Have you figured it out yet? 😉
Source Article from http://www.smashingmagazine.com/2013/11/25/the-smashing-book-4-mystery-have-you-figured-it-out-yet/