Geometric Puzzle Munificence

Having fallen under the spell of Catriona Shearer’s geometric puzzles again, I thought I would present the latest group assembled by Ben Orlin, which he dubs “Felt Tip Geometry”, along with a bonus of two more recent ones that caught my fancy as being fine examples of Shearer’s laconic style. Orlin added his own names to the four he assembled and I added names to my two, again ordered from easier to harder.

See Geometric Puzzle Munificence.

(Update 4/16/2020)  Ben Orlin has another set of Catriona Shearer puzzles 11 Geometry Puzzles That Drive Mathematicians to Madness which I will leave you to see and enjoy. But I wanted to emphasize some observations he included that I think are spot on.

“There’s a meta-problem,” mathematician Timothy Gowers recently mused, “that it’s vaguely on my to-do list to think about.”

Gowers, a 1998 Fields medalist, has done breakthrough work in combinatorics. Dude’s a Royal Society Research Professor at University of Cambridge. His to-do list is no doubt a catalog of deep and important mathematical questions. So what is this meta-problem nagging at him?


Catriona Shearer is a math teacher whose Twitter account features homemade geometry puzzles. But “puzzles” perhaps undersells them. These are puzzles that entice and entrance mathematicians of every stripe.

Puzzles that elicit caps-lock, triple-punctuated expressions of wonder.

“I don’t think I’ve ever seen anyone in my entire life,” says the mathematician Mike Lawler, “who has an eye for neat geometry problems like Catriona Shearer does.”

“These problems can’t just pop into her head,” insists Gowers. “Does she have a general theory? Or a nice bag of tricks? Or what?”

“Yesterday I read a tweet of hers,” chimed in John Carlos Baez, a leading category theorist, “where she said she’s not as creative as some people seem to think: she keeps using the same tricks over and over again.

“This,” Baez noted, “is also what Feynman said.”

2 thoughts on “Geometric Puzzle Munificence

  1. Thomas

    This is my first time coming across this website/blog. I am Thomas Tase from Botswana. I am a math tutor and an aspiring puzzlist/mathmagician. This internet address has a wealth of challenging math problems, articles and resources that have my attention. I would love to explore more and visit and see how i can legally use the materials here for educational purposes. Please dont hesitate to share with me anything via my email;

    1. Jim Stevenson Post author

      Thomas, you are free to use anything in this blog. Just credit where you got things as I have tried to do with the material I include. Certainly all my puzzles and problems come from elsewhere. A by-product of my efforts is to have people explore many of these sources to discover even more possibilities. I am glad you found the material interesting. Good luck.
      Of course, this relates to non-commercial and private uses. Any commercial use would need the individual permissions of whatever sources were involved in a given post.

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