I love getting mail at school that isn't people trying to sell me stuff...
He even provided me with an answer that was hidden so I couldn't cheat.
I pondered this puzzle for WEEKS. I showed it to my sister. She was stumped, too. I showed it to some students who happened to be hanging out in my room at lunch. We could not figure it out.
I actually never ended up figuring it out myself. I tweeted about trying to solve it, and someone tweeted back with the answer to the puzzle even though I had specified "no spoilers, please."
After seeing the answer, I'm not sure if I would have ever actually come up with the answer myself. But, I guess I'll never know now. It's a good reminder to me to not give the answers away too quickly to my students.
And, please, no spoilers in the comments for those who want to play along.