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Dr. Shapiro's Puzzle of the Day

Today's Puzzle

Monday, March 8
In the movies, when the bad guys want to prove that a hostage is alive, they release a photograph of the hostage holding the current day's newspaper. Such a photo could only have been taken on or after the date on the paper.

How would you stage a photo that could only have been taken on or before a given date? (Be creative! I'll post my favorite answers tomorrow.)

   


     Note: Clicking "Submit" will send your response to Dr. Shapiro.

Yesterday's Puzzle + Solution

Which one of the following sports has never been featured at the Summer or Winter Olympics?
  1. tug-o'-war
  2. biathlon (a sport consisting of alternate rounds of cross-country skiing and target shooting)
  3. sumo wrestling
  4. ballooning
  5. solo synchronized swimming

Solution The answer is C, with partial credit for D (ballooning appeared on the program only as an unofficial event). I don't know the history of the Olympics well, but I would speculate that sumo wrestling has not appeared because it is so overwhelmingly associated with a single country, which goes somewhat against the spirit of the Games. However, Japan is going to hold a sumo exhibition at the 2020 event in Tokyo. (Yes, I just wrote a sentence referring to a "2020 event" in the future tense.)

I expected "solo synchronized swimming" to raise eyebrows, but it's a thing! Or at least it was from 1984 to 1992. We think of synchronized swimmers as being synchronized with each other, but they're also synchronized to music, so the solo event is not a complete oxymoron.

Congratulations to yesterday's winners Charlie, Connor, Jacob C., Ena, Inca, Maddy, and Kate. Thanks to everybody who made a guess!

About This Site

Though he now teaches mathematics, Dr. (né Mr.) Shapiro's first job in a K–12 school was as a lunch monitor in Davis, CA. It was there that he originated the Puzzle of the Day, even rewarding correct answers with tickets in denominations like "15 points" (though without a clear idea of how he'd ultimately redeem these). Dr. Shapiro's favorite puzzle from this pre-professional era was "Tell me the location of the beehive on this campus."

Ten years later, Dr. Shapiro revived Puzzle of the Day at Proof School, writing each day's puzzle on a name tag. After 600 puzzles or so, he was just starting to feel normal about students reading his chest all the time when campus closed and the puzzle, like the rest of our lives, moved online. New puzzles are posted daily on school days.

Want to catch up on old PotDs? There's an archive currently containing puzzles from March to December 2020.