I like the idea a lot. Can anyone else imagine Z taking great pleasure in using a children's Dick Tracy decoder to create a secret message that the blue pigs couldn't figure out? I certainly can. It could even add a level of irony considering himself a "cereal killer" like 'ol BTK although the term serial killer wasn't even coined until the 70s sometime, I believe.
AK's example made me think of this recent secret coded message for some reason:
https://pbs.twimg.com/media/Bd527o5IQAAnHd5.jpg:largeIt's a long shot, Tahoe, but have you tried placing those decoder cards over portions of the 340 cipher to see if they would fit and yield any kind of message? Perhaps all of those extraneous non-letter symbols are just filler? The cipher is tidy enough that it would at least be possible to try. If you solve the damn thing this way and make a fortune in speaking engagements, just remember who helped you out, OK?
