Possibly the best thing about my "Nature of Math" course this fall is waking up to emails from non-math majors sending me links to math stories they've read on the internet.

In principle, at least, grading papers stops at some point. The dog, however...

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I asked students to define some special categories of hexagons and invent names for them. Some excellent submissions so far include the families of Squashagons, Boltagons, Extremely Irregular Hexagons, and Treeah Stars. (I'll leave it to the reader to imagine the definitions)

Assigning students to photograph instances of different frieze pattern symmetry types in real life has been one of the more rewarding problems for me, as a grader, recently.

I needed a slide to put up during online lectures, while students are responding to a question...

Thanks to twitter.com/eluthar/

I was told this rhubarb pie would take the taste of shame and humiliation out of my mouth, but it isn't working.

Ah-ha, the actual lyric was "Well known by those who know," and it was Samael. A monster track:

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Now I'm I'm puzzling over which band put the phrase "well known to those who know" in my brain. Carcass? Voivod? Anacrusis? Something like that. It's on the tip of my brain.

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It was a good reminder that ideas which are "well known to those who know" are *not* well known, obvious, or old hat to those who haven't yet encountered them.

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Using this game – although not this particular web page, which gives too much away – to kick off a discussion of infinity (and infinities) in my Nature of Math class.

Polling the students for their thoughts on who has the winning strategy was fun - there was a mix of opinions at the outset.

Finally found something I've been looking for: Nice, modern browser-based drawing tools for designs with dihedral, frieze, and wallpaper symmetry groups:


Wonderful mathematical reading:

"Here you can find a variety of mathematical texts on many different topics. One section is related to the “snapshots of modern mathematics from Oberwolfach”, the other section offers general background material connected to our exhibits and projects. We hope you enjoy your read!"

I'm a little starved for the mental stimulation and idea influx I get from good math seminar / colloquium talks (which I'm not getting at the moment). Anybody have any good sources for online talks of this type, preferably something where one could join, interact and ask questions?

"J. Siehler - 1975 – 2020 - RIP.
He died apoplectically repeating 'Quantifiers! Quantifiers! Use appropriate quantifiers when introducing new symbols into your proofs!"

This makes the construction of such a list either a very good or a very poor assignment, depending on your needs and purposes.

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It's well known that you can find eight 7-bit binary words all at Hamming distance 4 from one another (and 8 is maximal). What I never noticed before is that, if you start building such a list heedlessly, adding one new word at a time checking only that it's distance 4 from all the words already chosen, you CANNOT LOSE. You'll never get stuck; you'll always make it to eight. I have to think about that some more until it no longer seems to be a surprising and joyous geometrical conspiracy.

I wonder if anyone else had an, "Oh, I know her!" moment when watching Only Connect this week.

A problem of mine appears in the most recent Mathematical Gazette:
"Two unit squares are drawn in the plane with their edges parallel to the coordinate axes and their centres chosen randomly and independently in the region \(-1 \le x,y \le 1\). Determine the expected value for the area of their intersection."

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jsiehler's choices:


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