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Saturday, 2017 September 9, 20:01 — merch

a poster


Sometimes I search my blog for this picture and scratch my head in puzzlement that it’s not here, before remembering that I posted it on Google Plus back when I used that.

So here it is. Stephen Guerin (the shaven one) displays his canvas print of one of my designs.

The colors came out better than I hoped, in stark contrast to a couple of mugs with related designs that I got from the same shop.

Wednesday, 2017 February 8, 20:20 — merch

Klein bagel, mark N


I’ve had other designs made in steel but not this one. (The sintering leaves the steel highly porous, so liquid bronze is brought in by capillary action to fill it; the result is about three parts steel to two parts bronze – if I understand right. Hence the color.) (Later: I was mistaken: the steel powder is not sintered but glued; the bronze presumably burns away the glue.)

While it was on its way to me, I thought of some improvements. ( . . more . . )

Tuesday, 2016 May 31, 13:12 — bitterness, technology

hilarious title

On a private mailing list, a novelist asks for suggestions: what technological hobbies might a bright teenager have, in Oakland circa 1975? Chemistry sets were mentioned, among other things.

I may have had a chemistry set at age 8 or so; memory is spotty. A few years later we got an electronics kit, consisting of a collection of elements in Lego-like blocks. There was a booklet, starting with easy things like a light switch and an electromagnetic telegraph relay. (Maybe I thought the latter was easy because Dad and I had made one, about the same time as the possible chem kit).

Then on the next page was an oscillator or something. No explanation of why it was an oscillator. I thought, well, if I can’t see for myself why it’s an oscillator, evidently I’m not cut out for this stuff; so I quietly abandoned it.

My adolescence in a nutshell.

Of course it never occurred to me that perhaps there was no explanation because I was not expected to understand an explanation; I was expected to treat the oscillator as a black box. (Not that I had the concept of “black box”, either!)

Oh well.

Tuesday, 2015 December 29, 12:17 — me!me!me!

allonymy

A notice to renew my domain registration prompts thoughts of what I might have used instead: ansher, anwood, tonsher, tonwood ?

tonsher reminds me of an acquaintance whose bald spot looks uncannily like a monk’s tonsure — and that’s even funnier on a Jew. My own bald spot is not so sharply defined.

Sunday, 2015 June 7, 07:52 — mathematics, me!me!me!

logarithmic birthday

I’m exp(4) years old!

Monday, 2015 January 26, 21:51 — mathematics, merch

elusive avoidance

I’ve been designing printable models of the Lawson-Klein surface

w = cos(u) cos(2v)
x = cos(u) sin(2v)
y = sin(u) cos(v)
z = sin(u) sin(v)

As you can plainly see, this figure lives in S3 (positively curved 3-space), so stereographic projection can bring it into E3 (Euclidean 3-space) without adding more self-intersections. (It crosses itself at u=nπ.)

To minimize the distortion of the projection, I want the projection center to be as far as possible from the surface. One thing I tried was pursuit: starting with an arbitrary point P in S3 and an arbitrary point L(u,v) in the surface, move (u,v) to bring L closer to P while simultaneously moving P away from L. This gets me nowhere so far: either it fails to converge or P converges to the antipodes of L, which is also in the surface (change u by π).

Monday, 2014 November 24, 09:59 — me!me!me!, medicine

hidden dragon

For years I’ve occasionally had a mysterious itch at my lowest left rib, nothing showing on the skin. Now it has spread rightward at the same altitude, making me think: could this be mild shingles?

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