Monday, 2020 March 30, 10:35 — curve-fitting

Scribbles: The Ensmoothening, Part III

Many of the curves in this chart have some unsightly wiggles. That’s because, when a function of degree 2 or higher tries to approximate a piecewise constant, it tends to go back and forth across the target. So here instead I fitted each such function not to the piecewise constant directly but to the fit of the next lower degree.
( . . more . . )

Wednesday, 2020 March 11, 02:07 — merch

supply issues

I’ve had a number of mugs printed by Zazzle, and most of them came out gorgeous; but last summer I was peeved enough by a delivery cock-up to want to take my business elsewhere. Recently I got around to doing something about it, with even more disappointing results.

Threadless would not let me sign up. I can’t tell which of my address, handle and password offends it, let alone how.

Cafepress failed to upload my design.

Spreadshirt and CustomInk cannot do a wraparound design on a mug.

Who else is out there? Maybe I have cooled off enough to go back to Zazzle.

Monday, 2020 March 9, 20:18 — spam

pull the other one

This week I’ve had a flood of mail with titles like VIDEO OF YOU! and YOU GOT RECORDED!. A tweetmate asked me to save and share one, so here it is. ( . . more . . )

Wednesday, 2020 February 12, 16:57 — prose

a sense of place?

I read Jack Vance’s memoir, of which many pages say “We went to Ireland / Tahiti / Kashmir . . . found a pleasant cottage and stayed there for a couple of months, cranking out stories.” It would be pleasant to know what was written where! Perhaps Jack himself did not remember. But it is impossible not to imagine that “The Moon Moth” was conceived on the houseboat in Kashmir.

Thursday, 2019 November 28, 19:51 — mathematics

it’s in the literature

On a truncated icosahedron / buckyball / Telstar-style soccer ball, consider two adjacent hexagons and the two pentagons that are adjacent to both. These four faces can be removed, rotated by a right angle, and reattached, causing only a small change to the overall shape. Most fullerenes have at least one such patch.

If I ever get around to making more printable models of fullerenes, I would omit those that can be changed, by the above twist, into one of higher symmetry. I have a pretty good idea of how I’d go about listing the fullerenes and finding their siblings; but I do not have a grip on distinguishing symmetry groups of the same order – e.g., that of the regular tetrahedron versus that of a hexagonal prism – and a subgroup of one may not be a subgroup of the other.

So I got out An Atlas of Fullerenes in the hope of understanding how they did it – and happened to open to a chapter I had not looked at before, which covers the Stone-Wales transformation (for so it is named) and lists, up to C50 (15 hexagons), which fullerenes change with which.

The 812 smallest fullerenes are thus cut to 72 in 47 families. The biggest of these families has six remaining members, four with C2v symmetry (one axis of twofold rotation, and a reflection plane containing that axis) and two with C3 symmetry (chiral with one threefold axis). Their symmetry numbers are 4 and 3 respectively, but as C3 is not a subgroup of C2v I keep them all.

Surprisingly the ten families of C50 include two with no nontrivial symmetry at all.

Wednesday, 2019 July 24, 09:24 — merch

I ain’t Zazzling any more

You probably haven’t noticed the absence of a link in the upper left, “buy 2D printed objects”, which went to my catalogue on Zazzle: shirts, mugs, posters. ( . . more . . )

Tuesday, 2019 June 4, 17:11 — blogdom, me!me!me!, neep-neep

all the world’s a wiki

I toy with the thought of converting this here website to MediaWiki (which my host supports), as I am more efficient at editing there than at writing raw HTML in vi.

The wiki’s first articles would be:

  • Two-dimensional design
    • Hyperbolic tilings
    • Arrangements of the color gamut in the plane
    • Curve-fitting
  • Three-dimensional design
    • Ray-tracing
    • Solid printing
  • Posthuman speculation
  • Political speculation
  • Linguistics
    • Diachronics
    • Writing
    • Conlang

I’d continue to report new thoughts here, and then integrate them into appropriate articles. I wonder whether MediaWiki and WordPress play well together. I’m not aware of any personal website that combines blog with wiki, but it seems unlikely that nobody does it.

And now I wonder whether a wiki on my home box would help me keep track of the little files I write as notes on this topic or that, and the PDFs that I download to read someday, and the

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