Linkage for the end of the Fall term

This week’s hype (\(\mathbb{M}\), more, still more, even more, one more). And that’s just the Not Even Wrong posts; see them for a more thorough link and media roundup. Short summary: physicists ran a simulation of a quantum physics model that is unrelated to the conventional notion of wormholes from general relativity, sharing only a name with it. They used a quantum computer for the simulation even though it could as well have been run on a classical computer. And then they screamed from the rooftops that they had created the world’s first wormhole, apparently deliberately misleading everyone who didn’t read the fine print (including many major media outlets and research administrators) into thinking that they had brought into existence a physical wormhole.

When I viewed a recent blog post complaining about the increasing number of trackers embedded on social media websites (\(\mathbb{M}\)), including stats obtained using uBlock origin, I found that uBlock origin blocked 17 items from the post. On the social media websites I frequent (mathstodon.xyz and this blog), it blocks 0 items. Hmm.

Certain phrases, once so commonplace that you could use them in analogies to explain more abstruse mathematical concepts and be instantly understood, have fallen by the wayside (\(\mathbb{M}\)). If you try to use them in the same way now, you will be met by blank stares instead of understanding. They are archaic and need to be retired from this sort of use. Today’s example: “telephone line”.

Playable puzzles based on the nothreeinline problem (\(\mathbb{M}\)).

Can the same net fold into two shapes (\(\mathbb{M}\))? Matt Parker explores what’s known about polyominoes that fold into more than one cuboid, with a nice shoutout to Demaine and O’Rourke’s Geometric Folding Algorithms. Still unknown: can you find one that folds into more than three cuboids?

Another batch of three new mathematical Wikipedia Good Articles (\(\mathbb{M}\)):

How many \(k\)element subsets of \([1,n]\) can you find so that all pairs intersect? The answer is the Erdős–Ko–Rado theorem.

How many patterns of pairwise connections can the subscribers to a telephone system form? The answer is a telephone number.

Which graphs can you draw so that all vertices are one unit apart? The answer is a unit distance graph.


Helicoidal decomposition of a tetrahedron into four identical curvy shapes, closely related to the Hanayama cast “Marble” puzzle (\(\mathbb{M}\)).

I recently learned, from an article about the entertainingly amateurish fake statistics in a bad paper they published (\(\mathbb{M}\)), that dubious journal publisher Hindawi was recently taken over by somewhat more reputable journal publisher Wiley, and that Wiley is rightly worried about the bad reputation Hindawi is casting on them.

As a Wigner crystal is dynamically deformed, its grid defects move around “in a kind of cosmic way”. Simulations by Nikita Lisitsa and Ricky Reusser.

Tech Intersections: Women of Color in Computing (\(\mathbb{M}\)), upcoming conference at Mills College in Oakland, California, January 28.

Rogan Brown – Paper Sculptures (\(\mathbb{M}\)). Delicately cut traceries resembling microfauna.

What aspect ratios of rectangles can be used to tile a square? More. Two long Mastodon threads. A couple of pointers into the middle of them: For recursive \(1\)to\((n1)\) guillotine partitions, there’s a nice recursive construction for the polynomials whose roots give you the possible aspect ratios. And one way to form subdivisions of a square into equallyoriented similar rectangles is to start with a squared square or squared rectangle and then scale the axes.

Even those so oldfashioned as to become monks and build stone Gothic cathedrals in the wilderness use 3d modeling and CNC machining instead of painstaking hand carving (\(\mathbb{M}\), via). As they write, “Medieval builders were always on the forefront of the technology of their day … To build Gothic today, it must become a reality, not a romantic idea locked up forever in one’s head.” See also a related article on digital modeling for the Sagrada Familia.