Porridge - the ultimate camouflage?

Anyone like me who works in an office will have experience of the office kitchen, complete with communal fridge. If everyone plays fair, what you put in the fridge in the morning will still be there at lunch time. Not always the case in my office, as today I was reminded of an incident almost exactly three years ago.

A software developer (who remains anonymous to this day), having had his sandwiches stolen once too often (so, twice then), decided to apply his engineering skills to catch the culprit. The next day, along with a stern warning note pinned to the fridge, an out-of-place box of Weetabix Seriously Oaty appeared on the adjacent water cooler. Below are a couple of photos I snapped at the time on my mobile phone - can you spot the subtle modifications?

The box had no wires, and was fairly heafty when lifted - which I'm sure was not down to a full bag of wholesome oats within. I couldn't work out whether just placing a bare camera in the same spot would have been just as subtle, as the package stuck out like a sore thumb. It must, however, have been effective as after just two days the device had gone. No doubt the sandwich thief in our midst had been banged to rights. Well, either that or someone had made off with an expensive wireless video camera!