I think for a moment. "They have to look like they mean something, like there are clues hidden in them." I think for a moment. What kind of clues would drive them both to figure out what's going on? "Obscure references to cases that they both would get, but would look like nonsense to others. But, also enough 'white noise' to hide those references or it'll be too easy." I look around again. "And, we'd have to make ourselves look targeted, too."