In an old joke from the defunct German Democratic Republic, a German worker gets a job in Siberia; aware of how all mail will be read by the censors, he tells his friends: 'Let's establish a code: if a letter you get from me is written in red ink, it's false.' After a month, his friends get the first letter, written in blue ink: 'Everything is wonderful here: the shops are full, food is abundant, apartments are large and properly heated, cinemas show films from the West, there are many beautiful girls ready for an affair -- the only thing you can't get is red ink.' The structure here is more refined than it might appear: although the worker is unable to signal that what he is saying is a lie in the prearranged way, he none the less succeeds in getting his message across -- how? By inscribing the very reference to the code into the encoded message, as one of its elements. Of course, this is the standard problem of self-reference: since the letter is written in blue, is its entire content therefore not true? The answer is that the very fact that the lack of red ink is mentioned signals that it should have been written in red ink. The nice point is that this mention of the lack of red ink produces the effect of truth independently of its own literal truth: even if red in reality was available, the lie that it is unavailable is the only way to get the true message across in this specific condition of censorship.