My brother sent this to me, and bragged that it took him 20 minutes. (He used the word "gloat".) I stared at it in annoyance for a bit, tried guessing, but didn't try and actually figure it out. (Guessing is pretty stupid - doesn't help solve it even if you get it right.) Went away and worked.
This afternoon I looked at the Bill Gates story again with all the examples and then I just suddenly got it. Took 10-15 mins at the most. Maybe less, but I wasn't timing so...
HA! I beat my brother, anyway...
