We saw this mentioned over the weekend in the NY Times Magazine and did a little more searching. Designers (both professional and DIY) are embedding QR codes in product patterns. The two-dimensional product bar codes originated in Japan, and you can use a camera phone with decoder software to scan the design and translate a message. For example, the pattern on the cake above (from Craftzine) contains a secret note. More below.

The pattern above is by John Young (aka Tikaro), whose needlepoint design translates into the url for Wikipedia's "pillow" entry. You can generate your own QR Codes at several websites, including qrcode.kaywa.com, and use them for your own craft projects.
To read the NY Times Magazine article, click here.
Top Photo: Craftzine, Bottom Photo: Boing Boing

Comments (7)
~ runs for an Excedrin ~
but why?
Oh, I've just had a long day, 10 hours of graphic design and pixels up close in photoshop. And another 2 weeks of exactly the same. And reading the story behind this code thing, my head just feels a little wonky.
I saw them use it on posters and such for concerts for example here. You could take a picture with your mobile and order tickets if you have the web on it.
I second the why.I have just lost all sense of direction.
A very cool graphic idea, but why the heck would you try to create one on a cake?!? Can you even imagine how much patience you'd need? (I'd be done eating the cake lonnng before the design was finished!) Heh! Maybe if you take a picture of it with your phone you can order another cake! I see the advantage now. :)
hyperlinking reality. freaking awesome