I had no idea that I could have let the proverbial cat out of the bag when I linked to different ways of lacing/tying your shoes. But it turns out that the CIA used lacing patterns as ways to send messages (slideshow). It’s the visual part of Tinker, tailor, soldier… illusionist?

“The instant the performer sees the spectator take a cigarette, cigar, or pipe, he takes the packet of matches from his pocket, tears off one match, and holds packet and match ready to ignite the match,” the magician John Mulholland wrote in a manual in the 1950s. “He does these things openly because what he does can only be looked upon as a friendly and courteous gesture.”

Mulholland’s instructions were written not for stage magicians, but for the covert operatives of the CIA. At the height of the Cold War – in the era of nuclear missiles and submarines, amid the tangled cloak-and-dagger maneuverings of espionage and counterespionage – the agency was also secretly doing something else. It was trying to learn to do magic.

Fortunately it’s all been declassified. Whew!