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[personal profile] jack
On the way back I went to Heffer's Arts. That was very nice, it had the feeling of coming home that other specialist shops and libraries often have.

Everything has little pads of paper you can try a pen on. I'm glad to see I wasn't just imagining that custom -- I remember buying a pen somewhere like Smiths once, and being looked at as if I was insane when I asked if I could see it write. Always or never doing so makes sense, but at least it wasn't only in my head.

It's also useful the other way round. I'm sure you remember my classic anecdote of looking for seating objects for the Veizla, going into a shop and saying:

Me: Hi! Excuse me, do you have about thirty, all about this big, each a different design?
Them: Have about thirty what?
Me: Yes, exactly.

Here it's a lot easier. Just, "Excuse me," point to a clef drawn on the pad, "I want one that draws like that."

In fact, many of the doodles were very nicely done, I feel out of place :)

In the end, I got a calligraphic marker, which I think does what I wanted, though I find something else would be more appropriate later. I considred brush pens, and they're definitely a superior product for drawing overall, but a little delicate and wet for my feeling right now. I almost looked for some colours too, but decided I didn't want to go overboard, I could barely draw proportions, I don't know if I want to venture into the murky waters of shading :)

Date: 2007-10-01 12:06 pm (UTC)
From: [identity profile] cartesiandaemon.livejournal.com
I think you mean "extremum" rather than "turning point", since the former lacks the connotation of differentiability :-)

:) Mutter, grumble, *concedes unnecessity of differentiability of complexity*

On the other hand, I think zenith and nadir might have connotations of continuity, and possibly even differentiability, whereas "extremum"[1] applies in those cases, but suggests cases that *aren't* continuous. I don't just mean that last year was disproportionately complex but that:

* The complexity had been building up for a time
* And now had decayed sharply
* And implicitly, evolved over time

That strongly suggests something like a differential equation. As does the comparison to orbits. In which case, differentiability would be right.

Or at least, it might be at least as correct to mean "differentiability" with "turning point" as to suggest denying continuity with "extremeum"

Sorry, I felt obliged to defend my choice, even though I didn't choose it carefully at the time :)

[1] Extremum certainly applies to any function, but in colloquial usage is used more often when a more specific term like maximum (of a set), or maximum point (of a smooth function) doesn't apply.