Lol. Astute. The explanation and diagram are however, an oversimplification tabs lead to an internet misconception. There was no known “shoe lace code.” If you think about it- the number of messages one might need to convey to another are so numerous and specific to circumstances that it would be impossible/impractical for every agent to memorize them all. What’s more- any code know must change cyphers or be breakable over time. So if there was a “shoelace code” that was so complex and had to be memorized- quite the feat already- it would also have to be regularly changed and re memorized.
Why not wrote it down? Well- that defeats the purpose- being found with shoelace code documents wouldn’t just out an agent clearly enough to identify them to the enemies satisfaction- but the enemy could get the code- and the “discreet” nature of using laces to send messages in public (where you are being watched and listened to or may be-) is defeated if you are checking a little cheat sheet while looking at their laces anyway.
Perhaps even more important- as you point out- is that not all shoes have the same number of eyelets, the same spacing and so on. Also- anyone who’s ever laced sneakers artistically knows things like lace length come into play here. It simply wouldn’t be practical to have a code which held even a small percentage of useful messages, covered all shoe and lace variables, was secure and discreet, and could be memorized by agents.
So what’s the deal? These illustrations and the idea DO come from internal CIA intelligence guides for agents. Using laces for coded messages or signals is an IDEA for agents to use. The way it would work is that the parties meeting, or a small cell, would agree upon certain signals before meeting. These signals would identify the person you were supposed to meet and verify it was them and not a counter agent posing as them. Common other signals agreed upon might be things like a “no go” to call off the meeting on the spot and tell the other party not to proceed but to reschedule- or a signal to let the other know they’ve been made and to cancel the meeting and assume you are found out and so on.
So the “shoe lace code” was one possible way to send such signals- and the meanings and particulars would depend upon the individuals involved, and of course what their shoes were able to do. The manual clearly states that the examples given as to what the signals might say or how to show them are just examples and not to be used literally.
So one agent might lace all the “X’s” below the eyelets except the third from the top to discreetly signal they were the party to meet, or that a critical task had been done or so on. They could use more complex signals as well if both parties agreed and felt it needed-
But anything from a short with a missing button, or a button of different size/shape/color, a pocket protector with a certain sequence or position of pens and pencils, etc etc. The trick to it was/is- your signal and identification/verification in general is meant to be subtle and not stand out- a sombrero in A small Irish village is a clear signal but also may attract attention because it is so out of place.
At the same time- the signal cannot be so subtle that it could easily be accidentally replicated by a random person. Something like a backwards ball cap is going to likely not tip off counter agents most places- but in a crowded festival if another agent is coming to hand off a package to you and is just looking for the guy in the backwards ball cap near the entrance at noon.... he could easily give the wrong person the package.
Both agents: Stares at ground aggressively
FBI guy 2: your place or my place