Foo. Last night I told friends (the Ridenours) about once memorizing a ridiculously improbable solution merely for the purpose of pretending to discover it while sitting next to a stranger on an airplane, e.g.. I completely forgot about http://www.inwap.com/pdp10/hbaker/hakmem/games.html (Item 75). (Reminder: Item 70 should say bishop at KB8 (not KB7!)). --rwg Shortly prior, young Rohan Ridenour tweeted a peculiar optical illusion https://twitter.com/wolframtap/status/689927650245087232?lang=en Mystery: Notice the blank in (White .Black.Gray), sine qua "Tweet is too long" !?