in reply to Playfair cipher
The presentation is superb, as always. But you have outdone yourself on the visual effect during program execution! I admit that I've run the program numerous times now just to watch the dazzling output during the cipher-generation. It's really a lot of fun!
One of the subtle beauties of this obfuscation is that perl -MO=deparse doesn't really help much. (<shameless plug> In constrast with this obfuscation, where -MO=Deparse is actually necessary for revealing the hidden message </shameless plug>). It's also neat the way the deparse retains the positive-image/negative-image effect; the top half looks very much like a lighter shading of the bottom half.
You clearly spent a lot of work on this gem, and it's paid off!