Hidden interlocking joints date back thousands of years. You can find more recent examples in furniture museums and even toys/puzzles. Repeating prior art in a different form (mail order) doesn't qualify and new art either, according to legal precedence. I read the entire patent btw.
Anyone who thinks this is patentable is out of touch with how broken the patent system is. Congress has taken a stab at changing it but still hasn't done so. Try DAGS on "broken patent system". Patents today are used to stifle innovation because companies have the attitude that if they don't profit from something then nobody else should either. This thought process has royally screwed tech companies to the point where they can't develop any software without violating some patent. Most of which shouldn't have been granted in the first place. When a company can patent a button widget then you know the system is broken. An example you can related to, Microsoft had to change Internet Explorer to require you to click on an Active X control because of some patent troll. For those who don't know, patent trolls are companies that do nothing but patent every day things that haven't been patented yet. Then they sue for money.
The company in this thread is only trying to stifle innovation and competition. They're doing nothing to protect a new invention or idea because they haven't produced one. I'm sure if they were challenged then their patent would go out the window. To bad congress hasn't passed the reform bill yet (allows for easy challenging of frivilous filings).