2007 — Today's mystery object is...

Well, actually, I don't know what it's called. But it was the "security device" left inside the case of my DVD copy of "The Black Dahlia" when I bought it in WH Smith and, I don't mind telling you, it made extracting the DVD contained therein very tricky. (It stops you from being able to obey the imperative "PUSH" for starters.)

I'm fairly sure the metal strips contained within the white bit are the bits that trigger alarm bells when waltzed through the detectors at the exit. But since it also signally failed to set off any alarm signals as I left the shop, I reckon it's one for Donald Norman's next edition of The psychology of everyday things — not to be confused with Edward Tenner's Why things bite back (the deliciously unpredicted pitfalls of new technology or, indeed of any technology, in my opinion).