Saturday, 2021 April 10, 10:58 — history

second-generation royal dukes

Prince Charles succeeds his father as 2d Duke of Edinburgh. There are now three living British princes with the title “2d Duke of…”; how often have there been even two? ( . . more . . )

Tuesday, 2021 March 9, 23:03 — futures, medicine

dot product of Cupid’s arrows

The backstory of Methuselah’s Children, by Heinlein, involves a foundation to promote human longevity. One thing it does is study natural long-lifers by paying a bounty for marriages between people whose grandparents all lived 100 years or more.

Now here’s a stack of wacky ideas of mine. ( . . more . . )

Monday, 2021 March 8, 08:02 — cinema

Billy Budd

Last night I watched Peter Ustinov’s adaptation (1962) of Herman Melville’s story Billy Budd. In 1797, a young merchant seaman is drafted onto a warship, where his sweet nature is admired by all except Claggart, the cruel master-at-arms, who resents Budd’s inability to fear him (because Budd is too innocent to see evil in anyone). ( . . more . . )

Monday, 2021 January 11, 23:17 — me!me!me!

of our elaborate plans, the potential end

For three days I’ve had a fever – CV-negative, but likely my highest fever ever! – which provokes me to start this post that I had meant to do someday, listing some projects that I may never finish (or even begin).

Font-fitting. The idea is to design outline fonts to match certain old favorite bitmap fonts, dot for dot, using curves as graceful as possible. Two-thirds of my posts in the curve-fitting category relate to that project; I won’t recap here.

I have thrown up my hands in bafflement because the fittings often fail to converge. It would probably help if I could put progress on the screen, rather than in image files to examine afterward, but tutorials in that direction have bounced off my lazy old brain. (I’m willing to try more.)

Pseudo-fullerenes. I made some fullerene models using tables of coordinates found on the Web somewhere. (I think that material is gone now.) I found them unattractive, because the polygonal faces are often so far from planar that they’re hard to see as faces. So I’d like to do in software what I used to do with plastic tabbed polygons, back when I was first studying fullerene topologies on my own. (The company that distributed the kit is defunct.) That is, place some rigid polygons in space and have corresponding edges attract. To get started on this I need to know how to make a rotation matrix, given an axis (as a vector) and an angle, for which I have not found a comprehensible cookbook algo.

Tesseract sponge. Of the 28 convex uniform tilings of Euclidean 3-space, 11 can be generated by reflection in an irregular tetrahedron of mirrors. If you place a plane so that it cuts four of the tetrahedron’s six edges (there are three ways to do that), and apply Surface Evolver, sometimes the surface converges to an edge, but otherwise you get a triply periodic minimal surface.

How about in non-Euclidean space? The uniform 4-polytopes can be thought of as tilings of a hypersphere, and most of them can be generated in the same way. Sadly, in these tetrahedra Surface Evolver converges to an edge in every case. But I should get something pretty if the surface is constrained to cut the tetrahedron’s volume in half. It would be nice to find someone who has worked with Surface Evolver in curved space with a volume constraint!

I’d start with the symmetry system of the tesseract, which happens to be the only nonprismatic system in S³ with two different kinds of mirrors (four on the coordinate planes and twelve diagonal); in the others, each mirror takes on all four roles in different instances of the fundamental simplex. So my model, in stereographic projection, would look like a lentil, bounded by one mirror of each set.

3-tiling catalog. In 2006 I made pictures of the Euclidean tilings mentioned above, for Wikipedia. I would love to do the same for each of the Thurston geometries; there are I think 64 (plus two infinite families) in S³, about 230 known in H³, 18 (plus two infinite families) in S²×R, and an infinite number in H²×R (I have in mind a selection of 36). I have no idea whether the three more exotic geometries admit any uniform tilings at all. Need a non-Euclidean ray-tracer!

Wednesday, 2020 December 16, 05:22 — music+verse

a wave in the air

“Radar Love” (1973) is the biggest hit of the Dutch band Golden Earring. Some folks strongly prefer a cover (1989) by White Lion. I don’t; is there a reason for that, other than my notorious conservatism?

White Lion’s version fills the ears more fully, and I can understand that some fans prefer that. But when it’s all high energy all the time, there’s no room for crescendo. Also, I find the implied silences of the original more appropriate to the story of the lonely night road. The entry of an organ at 2:38 and lead guitar at 2:48 suggests headlights appearing in the distance; they need the darkness for full effect.

Friday, 2020 October 30, 07:47 — general

bubbling shelves

I have more books than shelf space. I assume that some of my readers can say the same.

In my previous apartment, where space was even scarcer, I had one shelf beside my desk for the reference books that I use most often. After consulting such a book, I put it at the end of that shelf nearest my hand (I’ll call that end the head). How might I extend that principle to many shelves, without shifting all the books every time?

Initially all the books are in boxes (with a catalog telling me which box each is in). When I take a book from a box, it goes to the head of the first non-full shelf. If all shelves are full, it goes on the last shelf, and the last book on that shelf goes to a box.

When I take a book from a shelf, I return it to the head of the previous shelf (if any) and, if necessary, move a book from the tail of that shelf to the head of the next shelf.

Can you improve this scheme?

Wednesday, 2020 August 26, 15:18 — cartoons

curious about causality

Without trying, I can think of five webcomics authors who changed their pronouns long after they started posting: Dana Simpson (Ozy and Millie), Joey Alison Sayers (Thingpart and now Alley Oop), Allison Shabet (Deadwinter), Elli Stephens (Goblins), and now Maelyn Dean (Real Life).

Is there something in the ink?

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