So, having decided to go with Batman villain The Riddler for my halloween costume (the green-question-mark-blazer-and-bowler-hat version, not the original spandex catsuit one or the more recent tattooed metrosexual one) I’ve been paying more attention than usual to various kinds of puzzles and brainteasers. Two of which I’m fond, for those of you who are getting too much done: notpr0n has been around for ages and seems likely to live up to its claim as the “hardest riddle on the Internet,” though apparently now there’s a charge to play the higher levels, so who knows for sure. Some of the ones I got through can only be described as fiendish. Far shorter and easier, but just tricky enough to be a satisfying way to kill a little time, is Seen on Screen by Bart Bonte.