even the most convincing possible single character message isn't going to be very useful at convincing anyone of anything.
Who knows what eldritch horrors lurk in the outer reaches of Unicode, beyond the scripts we know?
Unspeakable horrors! However, unwritable ones?
Update 2013-09-05.
I have since played two more AI box experiments after this one, winning both.
Update 2013-12-30:
I have lost two more AI box experiments, and won two more. Current Record is 3 Wins, 3 Losses.