If you see two X's in his lacing, the package is at the alternate drop site.
If he has 3 X patterns, you're burned! Make your way to the safehouse after losing any potential tails.
Glance quickly, agent, and keep moving.
> Every Tuesday, shortly after 7:00, a British MI6 officer would take a morning stroll at the Kutuzovsky Prospekt in Moscow. He would pass outside a designated bakery at exactly 7:24 a.m. local time. If he saw Gordievsky standing outside the bakery holding a grocery bag, it meant that the double agent was requesting to be exfiltrated as a matter of urgency. Gordievsky would then have to wait outside the bakery until a second MI6 officer appeared, carrying a bag from the Harrods luxury department store in London. The man would also be carrying a Mars bar (a popular British candy bar) and would bite into it while passing right in front of Gordievsky. That would be a message to him that his request to be exfiltrated had been received.
It reminds me a joke about Soviet spy arriving in Berlin and caughting stares from everyone around. What's wrong with my cover? Is something gives me out? Maybe it is a parachute? Or AK-47? Ah, it should be blue Slavic eyes! And he wears a sunglasses just in case.
I took it to mean that the MI6 agents were under diplomatic cover. It would not be strange for British diplomats to carry or eat British things, right? And it's also a decent defense against an accidental signal, since non-agents would naturally not have Mars bars nor bags from Harrods.