Linkage

Trying to watch Olympics replays on Roku / NBC Sports is an exercise in frustration (\(\mathbb{M}\)):

• Up to 14 unskippable ads in a row
• Trying to fast-foward over breaks in sports action gets into a broken mode showing the same ads over and over while the underlying fast-foward goes on with disabled controls
• Rewinding to content you missed while uncontrollably fast-fowarding gets back into ad overload mode.

Who designed this unusable app and why do they think this will bring me back for more?

Rankings in all-play-all competitions (like group play stages of many Olympic games) typically use total numbers of points for wins. It’s simple, so audiences understand it. But really you might want to do something more complicated, like finding a ranking having the minimum number of upsets. The good news is that point score approximates the minimum-upset ranking (\(\mathbb{M}\)).

Topology is witchcraft (\(\mathbb{M}\)): link goes to animated gif of surprising disentanglements, made possible because topologically things were never tangled to begin with.

Facebook shuts down the personal accounts of university researchers studying how Facebook violates its users’ privacy in targeting political ads (\(\mathbb{M}\), via), citing as an excuse to do so…its agreements with the FTC over its violations of user privacy. Mozilla weighs in on why Facebook’s side of the story doesn’t hold water.

Muboard (\(\mathbb{M}\), via). There are any number of demo sites where you can type LaTeX math and get mathjax to format it for you in your web browser window, but this one looks like a good choice for sharing your screen when conferencing, office hours, etc: markdown for the non-math formatting, set up to look like a blackboard, with no unnecessary distractions, free to copy or modify.

The truncated octahedron can tile space, forming the bitruncated cubic honeycomb (\(\mathbb{M}\)). One of my neighborhood playgrounds has a climbing structure in this pattern, so kids can learn some geometry as they play. It wasn’t easy to find views without distracting background houses, but here’s one straight up from below its center.

I used this set to test out Lightroom instead of Photoshop for processing photos, with settings on auto. A few more shots. See discussion for another tessellation-based play structure and its grown-up architectural relative, the Nakagin Capsule Tower.

Guardian, by sculptor Susan Latham (\(\mathbb{M}\)). Its strange crescent moon or fortune cookie shapes are what you get from two overlapping circles intersecting in a vesica piscis, by folding the center arcs to make the two outer arcs meet. See also a short animation of this folding process and mathematical analysis by Klara Mundilova and Tony Wills.

‘Tortured phrases’ give away fabricated research papers (\(\mathbb{M}\), via, via2, see also). The gist of the story appears to be: paper mills are using automated synonym replacement to hide plagiarism, producing odd wording (“irregular timberland” for “random forest”, in the math/CS sense of forest), and bypassing normal editorial processes in hijacked established journals, particularly through topical special issues.

Joel David Hamkins tries to visualize the power set of the naturals (\(\mathbb{M}\)), showing also that it contains all countable partial orders.

Given recent news breathlessly hyping the “discovery” that the people of Sippar, in the First Babylonian Dynasty, knew about and used the Pythagorean theorem, based on the existence of rectangles in a land survey, I think maybe it’s relevant to point to Eleanor Robson’s review on the Pythagorean theorem in First Dynasty Sippar, citing work on the topic back to 1916. It’s “Three Old Babylonian Methods for Dealing with Pythagorean Triangles”, J. Cuneiform Studies, 1997 (\(\mathbb{M}\)).

The WADS (Algorithms and Data Structures Symposium) and CCCG (Canadian Conference on Computational Geometry) conferences were online this week (\(\mathbb{M}\)). The talks were mostly live on zoom rather than prerecorded, and although recordings exist temporarily, they’re only available to participants. The proceedings are online and public, though. The WADS proceedings through Springer LNCS is paywalled but the CCCG proceedings is free.

Steinitz’s theorem (\(\mathbb{M}\)), showing that the graphs of convex polyhedra can be described in a purely combinatorial way using only planarity and connectivity, and (through its proofs) describing how to turn a graph into a polyhedron. Now a Good Article on Wikipedia.

Etienne Cliquet makes kinetic artworks by cutting and folding sheets of paper, floating them on water, and filming them as the water causes them to unfold (\(\mathbb{M}\), via).