I like paper. Part of this, of course, is because I love to read, but there's also the smell and the heft and the texture of it. Flipping through a book can be a wonderful experience even without the words on the pages, just because of the feel of paper on finger tips. Books smell good, too, whether they're new or old. So sometimes I flip through a book even if I don't feel like reading it, just for the feel of flipping through the book.

In a brief break this afternoon to rest my eyes from the monitor and let the world regain non-pixelated edges, I flipped through Desolation Island, the next of the Patrick O'Brian books in my queue (The Mauritius Command was fun, by the way). I wasn't paying a great deal of attention to the words, though I sometimes paused to sample a sentence. But an indented passage of text caught my eye, and I stopped to read

Before my bed, clear moonlight
Frost on the floor?
Raising head, I gaze at the moon
Bowing head, I think of my own country.

Winnie taught me that poem last weekend! At least, she tried to teach me; I remember how to say the first two lines in Cantonese, but when I was practicing I mistakenly said chicken head instead of raising head, and promptly forgot everything from there on. I laughed at the coincidence, and that broke the sour mood that I hadn't even realized I'd fallen into.

This morning, like so many other summer mornings, the sky over Berkeley was overcast. But the clouds broke in the afternoon to let the sun through, and so I extended my break to take a walk. I went to the office to pick up a book, then wandered through downtown Berkeley to Safeway to buy fruit. Jazz music, the smell of cheese, and a queue of customers wound their respective way out of Cheeseboard Pizza as I passed, and the smell of coffee and the sound of espresso machines wafted out of the cafes. I passed a seeing-eye dog leading a blind woman and a woman walking a blind dog with eyes clouded by cataracts. I heard conversations in Spanish and Mandarin and English, and perhaps in Russian and Greek as well. As I made my way home, the sound of the BART train passing through the tunnel mingled with traffic noise and shouts from a soccer game in the park. And I walked and looked and listened, and hummed Walking in Memphis under my breath, and was pleased with the world.

Cities and neighborhoods have personalities. Getting to know a place is a little like getting to know a person. There are first impressions, sometimes right and sometimes wrong; there are things the city shares with one person but not with another; there are shades and shifts and changes over time, and there are things that stay pretty much the same. And we get to like a place, or dislike it, or live with it happily, or ignore it, or treat it nobly or ignobly in many of the same ways we treat other people.

So I wandered, and I let my mind wander. I thought about how alien Berkeley felt when I first came, how it became more familiar over time, how it changed as friends arrived and left. When I stopped at the office to pick up one of my books on eigensolvers, I read an e-mail from a professor at College Park, who I hadn't heard from since I took his course on ODE theory as an undergrad; and so I was thinking about Maryland, too. The squirrels will be out in force on campus at this time of year, sporting around the end of McKeldin Mall like a particularly playful invading army. It's probably hot and humid, perhaps with a smell of rain in the air, quiet as campuses always are in the summer.

And then I came back and sat down and discovered that I didn't feel like returning to my strivings with Matlab. I picked up a fountain pen and thought for a moment about writing a letter; but after playing with it for a moment, much in the same spirit as I flipped through the book earlier in the afternoon, I put the pen down. I wasn't sure who I would write to. So here I write, and, it would seem, here you read.

And now I'm going to have some bread and water (a wonderful combination given an undeserved reputation by association with solitary confinement), and do some more work.

Something to ponder if you are interested in shock waves or phase transitions, or if you're just stuck in traffic -- could controlling a few cars stabilize the state of stable traffic flow when a jam would usually occur?

In college, we played the Vacuously True Statement Game. Example: Every time I've been abducted by space aliens, they've treated me well. The statement is true, since I've never been abducted by space aliens (at least to my knowledge). Related amusements include:

• The Alarmist Trivia Game -- Dihydrogen monoxide can be fatal when inhaled!
• The Escalating Exaggeration Game -- This pack must weight fifty pounds. What's that, fifty kilos? Yes, it's amazing that I'm not squashed under this fifty kiloton pack. This is one of Patxi's favorites.
• The New Constant Game -- Someday, I'll have an important class of numbers named after me. Like the set of all even primes. Like the Vacuously True Statement Game, this is Mike's invention.
• The Ridiculous Song Game -- Self-explanatory. Since this is one of my favorites, there are examples in the archives. Chopsticks, Edelweiss, and the Surprise Symphony are my favorite templates.
• The Flagstaff Game -- In which any geographical location you care to name is placed in relation to Flagstaff (usually within walking distance). This is also Patxi's contribution.
• The Ramsey Theory Bites Dance -- It doesn't, really. But after Mike and I got to prove the fifth or sixth variant, it did start to get old.
• The Spackle Convention -- If your friend told you he'd eat a gallon of spackle if he were shown wrong, would you, too, quickly change topics?
• X Wars -- How many sets of xeyes can your host support before it becomes unusable?
• Boardy -- This was a variable name from a chess program capable of bending the computer into pretzels, written in AP Computer Science by Will. Chant it over and over again, and it becomes fantastically funny. At least, it does if you're me. Or if you're Will, for that matter. I don't think it ever amused anyone else quite so much.

I think it's time to eat now.

From the farmer's market: fresh salmon and heirloom tomatoes
From the Cheeseboard: asiago bread and tomato salsa
From things around the kitchen: spices and peppers and onions
From Winnie: sweet corn on the cob

I'm really looking forward to dinner this evening.

There are days when editing, for me at least, is a way to slack off.

Now, in college I had a friendly argument with friends which went on intermittently for a month or so before we all dropped it. I claimed that vacuuming, washing dishes, cleaning the bathroom, and eating meals are all -- potentially, at least -- ways of slacking off. I like to eat, and I like to clean -- eat something messy, wipe a dish off, and admire the sparkle. It takes little effort, and the results are immediate. Now, these activities are necessary, and I would probably do them even if I didn't enjoy them. But I do enjoy them, and I figure that if I eat and clean when I have other, more urgent, and perhaps less enjoyable tasks pending, then the eating-and-cleaning time counts as goofing off. My friends disagreed, but they never really convinced me.

Therefore, I feel vaguely guilty for spending the afternoon editing when I should probably have been writing code or running experiments. I'm fond of my red pen, probably because very few other things in my life involve such a vivid primary color. Sit me down with a red pen, a cup of something warm, and a manuscript in progress, and I'll be happy as a clam. Writing new text is hard work, but revising existing text is fun. Maybe I enjoy editing for the same reasons that I enjoy cleaning: it's easy, and the results are immediate. Still, while I don't feel guilty about my editing time (certainly not as if I should be chastised with scorpions as one high-school teacher put it), I also think it's fair to say that I was slacking off. At least a little.

I also goof off in other ways, of course. I read books, and I've taken to watching television sometimes. I make up bad puns (does anyone else think about legally changing their name to Bic Pentameter?); I go for walks; I people-watch; I hang out with friends; I surf the web. Sometimes I just stare into space, though I can't imagine how I look any different when daydreaming than I do when proving a theorem or thinking out how to design a program. Apart from some extra enthusiasm about things mathematical and a tendency toward speech patterns more commonplace in the nineteenth century than in the twenty-first, my distractions and my habits of work and play are in the normal range for a modern-day male American in his mid-twenties. And so I'd guess that there are plenty of other folks out there who, like me, sometimes engage in goofing off of the necessary sort, whether by fixing a car, cleaning, or doing some other enjoyable chore in place of something more onerous.

Pete, feel free to disagree with me the next time you feel like goofing off.

• Currently drinking: Osymanthus fancy black tea

From Patrick O'Brian's The Mauritius Command:

   Certainly, said Stephen. To the ultimate crosstrees if you choose: I too am nimble as an ape.
   Jack was moved to ask whether there were earthbound apes, as compact as lead, afflicted with vertigo, possessed of two left hands and no sense of balance; but he had seen the startling effect of a challenge upon his friend, and apart from grunting as he thrust Stephen up through the lubber's hole, he remained silent until they were comfortably installed along the studding-sails, with their glasses trained upon the town.

What a wonderful sentence!

• Currently drinking: Black coffee

A cup of tea or a glass of lemonade, sipped in solitary quiet, is a wonderful thing. Eating alone is usually not as fun. But there are exceptions.

I eat fast. I often make cold meals of fruit, bread, and cheese, and when I do, it usually takes me more time to cut things up and wipe away the crumbs than it does to actually eat. Cold leftovers disappear go just as quickly. But I also like to cook, and it's a good thing. Cooking can be almost as meditative an activity as preparing tea (not quite, but almost); and I find it easier to take my time enjoying hot food. Also, while I enjoy fresh fruits and vegetables and bread, not all the food in the kitchen is fresh. I've eaten stale bread with molding cheese and wilting spinach. I've also used stale bread, Cheese of Ages, and wilted veggies to make french onion soup and omelette fillings. The soup and omelette were good; the sandwich was miserable.

This evening, I split the difference. I had fresh olive bread and good black cherries (on sale at Safeway), and I also made an omelette filled with the last of the munster cheese (which wasn't exactly bad, but needed to be used), the last of the zucchini (in about the same state as the munster), some tomato, and an excellent jalapeno. I cooked the vegetables for the omelette filling in olive oil with a little black pepper, and added them after the cheese melted. It was good, and it was hot, and I ate with gusto tempered by caution against burning my mouth.

What better way to end than with a hot beverage of choice?

• Currently drinking: Hot water with lime

• According to StarDate, the navy bounced the first voice transmission off the moon fifty years ago today.
• The CBC has an entertaining and informative brief history of beer.
• Smithsonian Magazine has an interesting article on the legend -- perhaps apocraphyl? -- of William Tell.
• In the July issue of The New York Review of Books there is a review entitled The Lost Art of Eating. It is inspired by Roy Strong's Feast: A Grand History of Eating, which I think I must add to my to-read list; but like most NYRB reviews, it wanders entertainingly far afield from the topic of the book.
• I've mentioned Mark Kurlansky's Salt: A World History before. It's a fascinating book. So is The Basque History of the World by the same author (who also wrote Cod: The Fish that Changed the World -- do I see a pattern?). I stumbled across a rather shorter history of salt online, but the book is more entertaining.

I think now is a good time to close the computer and take a walk.

This morning, I read an amusing revision of Asimov's three laws of robotics written by Mark Zimmermann after watching I, Robot. There was also an NPR segment on the same film earlier this week, and a review by Gary Westfahl at Locus Magazine. The review confirm what I'd guessed from the trailer: that I, Robot is an action movie more influenced by Will Smith than by Isaac Asimov. It seems a pity. But then, I enjoyed Independence Day; why should I be disappointed to hear that I, Robot is another movie in the same style?

In a talk given at BookExpo America, Ursala Le Guin commented on some assumptions about fantasy. Though none of her examples are drawn from science fiction, her points apply more generally. The third point she makes seems particularly apropos:

Assumption 3: Fantasy by definition concerns a Battle Between Good and Evil. This is the one where the cover copywriters shine. There are lots of fantasies about the Battle Between Good and Evil, the BBGE, sure. In them, you can tell the good guys from the evil guys by their white hats, or their white teeth, but not by what they do. They all behave exactly alike, with mindless and incessant violence, until the Problem of Evil is solved in a final orgy of savagery and a win for the good team.

Westfahl echoes Le Guin's sentiment in the first paragraph of his review:

Contrary to some published reports, the film I, Robot does in one respect powerfully recall the thoughts and writings of Isaac Asimov. Unfortunately, what came to my mind while watching the film had nothing to do with Asimov's robots, but was rather the statement that echoes through his early Foundation stories Violence ... is the last refuge of the incompetent which explains why Asimov's fans will regard this film as an appalling travesty.

Violence need not be the anathema of plot and character development; just look at the death toll in Hamlet, in which Shakespeare gives the final soliloquy to a secondary character for lack of any main characters left alive! And while Asimov created the character of Salvor Hardin, whose motto about violence is the source of Westfahl's quote, he also made Hari Seldon proficient in a judo-like martial art (twisting). Still, the point is made: a shoot-em-up cannot be fairly said to be based on Asimov's ideas if those ideas are displaced by mayhem.

A good screenplay based on an Asimov book could not be the same as the book. Books contain details which don't fit easily into the dialogue and scenery; and book authors can deliberately omit details in a way that would be hard for a screenwriter to manage. Peter Jackson's adaptation of The Lord of the Rings was successful in part because of the beauty of New Zealand's landscape and the power of Howard Shore's score, elements which were clearly not part of the books. Jackson paid respect to Tolkien's ideas and intentions where it was appropriate, and he interpreted, added, and elided elements as needed to craft a film. The result was a grand success, and, I think, faithful to the spirit of the book.

I think many of my favorite science fiction and fantasy books would be very difficult to adapt to the screen. Jackson managed better with Tolkien than I would have imagined, but attempts to interpret Frank Herbert, Robert Heinlein, and Isaac Asimov have all fallen flat. I think the thing that separates the successful from the luckless is the skill with which the filmmaker sifts out the character, plot, and high-level ideas and makes them independent of the author's crafting of details. Tolkien was a linguist; Heinlein was an engineer; Asimov was trained in the physical sciences. Vernor Vinge was a professor of computer science for a time; Kim Stanley Robinson received a doctorate in English; Jerry Pournelle studied a variety of things before he turned to writing (and picked up two doctoral degrees along the way). Mary Doria Russell, whose books I enjoyed recently, has a day job as a researcher in paleoanthropology. Not all my favorite science fiction authors hold advanced degrees, but almost all of them have some area of intense interest and long study, and it shows in the way they write. Tolkien wouldn't be Tolkien without the created languages. Heinlein wouldn't have been nearly such fun if he didn't tell the details of the control systems on his rocket ships. Part of the fun of Vinge is reading about his interstellar version of Usenet, or about his vision of programming turning into archaeology as computer systems become too complicated and baroque for anyone to truly understand. David Weber's battle scenes would fall flat without his interest in military history and his thoughtful analysis of the ways in which different technologies would necessarily change tactics and strategy. But none of these detailed interests would translate well into a movie.

I'd say that's a good reason to keep reading... as if I needed an excuse.

• Currently drinking: Oolong (which I now know means absent-minded in Cantonese)

I think the extended complex scaling technique sometimes used in quantum mechanics computations is extremely similar to the perfectly matched layer methods used for acoustics, Maxwell's equations, and (most recently) elastodynamics. Sadly, while I understand the notion of a PML at this point, I don't know enough about quantum mechanics to decipher much of the available literature on ECS.

One day I'll have to learn some quantum. And some statistical mechanics. And some economics. And some more topology. And some Mandarin. And...

To the tune of My Favorite Things:

I take my car to a quantum mechanic.
He's a little bit strange, and perhaps a bit manic.
He strokes Schrodinger's cat, and uncertainly sings:
What are a few of my favorite things?

My position! My momentum! All that folderol.
I can know one of two of my favorite things,
So why can't I know them all?

(The answer to that last why question has something to do with non-commutativity of certain operators -- as I understand it, that's really what the uncertainty principle is about. I might be able to say something more if I actually understood something about quantum mechanics; alas, knowing something about spectral theory for continuous self-adjoint operators is not quite the same.)

• Currently drinking: to the confusion of my foes?

I was at the SIAM Annual Meeting in Portland from Tuesday through today (Friday). However, I've had relatively little time accessing, and I've spent more time on the human sort of networking than on the computer sort. I'll catch up on e-mail and such over the next few days.

The technical program was interesting. Topics that I found particularly exciting included:

• Shear wave imaging

  When a doctor feels for lumps, she moves her fingers back and forth. A lump is a place where the subsurface tissue is more resistant to the shearing force that comes from rubbing across the surface. We already use ultrasound imaging, which involves compression waves traveling through tissue. Why not use the much more slowly-traveling shear waves, too?

• Splines and Boeing

  There was a keynote talk about computations done at Boeing using spline. The talk involved a lot of pretty pictures, and also a back of the envelope calculation in which the speaker estimated that there were probably about half a billion spline calculations done in Boeing systems every day.

  A half billion is a lot.

• Equation-free and multiscale models

  Mathematical modeling usually involves creatively fuzzy vision. If you want to model a weight hanging on a spring, you can try to model every atom in the system, and go nuts; you can do some averaging and model the spring by a set of partial differential equations, and keep people like me employed; or you can assume that the amount that the string stretches is roughly proportional to the amount of weight you hand on an end, do one experiment to find the constant of proportionality, and go for a walk.

  We have a lot of tools, both analytical and numerical, that work well for systems described by partial differential equations. But what about systems of particle interactions in which we're not smart enough to write down a continuous approximation? It turns out that it's sometimes enough to posit such an equation exists (and is continuous) -- without writing it down. You use your microscopic model to fill in what's happening in a few places, and then use the data at those points to fill in everywhere else. The idea is simple, the details are hard, and the whole effort is immensely interesting.

  It's also sort of astounding. How do you solve an equation without the equation? Equation-free modeling sounds like it ought to be the title of a Zen koan -- if Zen koans had titles and a flair for the technical -- but it was actually the title for one of the keynotes.

  A related area, less magical-sounding but equally profound, is multi-scale modeling. It's exactly what it sounds like: there are some things that happen very quickly and some things very fast, or there are some things that happen over a large area and some over a small area. If you looked at everything finely enough, you'd see the whole picture, but that's unbearably expensive. So you selectively put on glasses, and build some machinery to connect the very small to the very large.

• Implicit codes and software engineering

  We didn't want to tell the scientists they would have to change their codes a lot. The scientists hate that.

  Very true. I'm glad to see it recognized.

• Google

  We'll take Google as an example. Nobody knows quite what Google does, but we think it might be this.

  Web searching is a hard technical problem involving some very interesting ideas from numerical linear algebra. Marveling at the math is almost as much fun as marveling at Google.

• Eigenvalue problems

  I talked about one type of eigenvalue problem. Other people talked about different types of eigenvalue problems. I enjoyed the talks and the conversations.

More generally:

• Portland is impressive. There is a book store here that covers an entire city block, and a companion technical book store which is also extensive. Several of us went there this afternoon; we met others with the same idea. We should have just held the last session here.
• There are other impressive things about Portland, too, like the train system and the people. And did I mention the book store?
• Through Thursday, there were vendor booths with several major technical publishers and a handful of people selling software. I bought two books, a little monograph on Lanczos algorithms and Matrix Algorithms, Volume II: Eigensystems by Pete Stewart. I've intended to buy the latter since it came out -- a year ago? two? -- and I haven't finished gloating over it yet.
• I still find it astounding to watch human networks at work. I met a lot of people at the meeting -- that's much of the point, after all. Some of them I knew from reputation, some of them I didn't. In any case it usually took all of fifteen seconds of conversations to find someone we knew in common, and often a common research interest. Also, I'm always impressed by how friendly and approachable the people at these meetings are.
• I'm so glad that I took classes on fluid mechanics and finite element analysis. I cannot imagine enjoying this meeting half as much as I did if I knew nothing about those topics.
• My talk went well. I'm glad it's done.

While I'm finishing my coffee and waiting for clean socks from the drier, some notes on recent and moderately-recent reading.

• Henri Poincare. The Value of Science --

  Poincare was a luminary of mathematics and physics who contributed, among other things, to the study of dynamical systems (he won a prize for his work on the three-body problem) and topology (analysis situ, as it was known at the time). E.T. Bell called him the Last Univeralist for the breadth of his work. In addition to being a leading scientist, Poincare was a science writer, and The Value of Science is a translation of several of his popular science works from the end of his life, near the turn of the twentieth century.

  I've read some of The Value of Science, but I haven't exactly made rapid progress. I expect I would enjoy it more if I read French; while the translation is competent, it still has the odor of a translation about it. Also, while interesting, the topics covered are mostly familiar. The familiar topics and the slightly stilted translation together make my reading leisurely and sometimes drowsy.

• Patrick O'Brian. Post Captain and H.M.S. Surprise --

  I wish I read more books with lines in which one main character cries to the other You have debauched my sloth! The books are fun and easy to read, despite -- or perhaps even because of -- the frequent nautical jargon. The next two O'Brian books are in queue.

• Roger Zelazny. The Great Book of Amber --

  I bought this collection a while back while on a let's buy classic fantasy I haven't read kick. The Amber books are regarded as classic for a reason. There are some interesting premises, and the books move along smartly. I was glad to see the end of the last one, though. For all the plot twists -- and all the plotting -- the books seem to have an endlessly inconclusive quality to them, reminiscent of Neil Stephenson (but with a better editor).

• William Gibson. Pattern Recognition --

  One of my friends has commented that Stephenson's writing changes meaning completely if you don't pay attention to every word. I only half agree with him, but Pattern Recognition makes a persuasive argument for his case. Looking back, the plot seems a little off, but the writing is wry, witty, and dense in a way that makes it difficult to read some paragraphs only once. There are no cyber-cowboys or vat-grown ninjas, but the imagery is fully as developed and surrealistic as anything in Neuromancer and its successors.

• Bill Bryson. A Walk in the Woods --

  I'm only half done, but it's funny and fast-reading so far. If I like the second half as much as I liked the first, I'll probably check out some other things Bryson has written.

When Jim left last Tuesday for a week at home, he left behind a bag of donated zucchini. Eat it! I don't want to see it when I come back, he said.

So here are 2.5 ways to prepare zucchini if you're not the greatest zucchini fan. All were shared with and approved by Winnie, so there is at least one other person who thinks they're good ideas.

Zucchini stir fry:
I used baby bok choy, a green pepper, snap peas, and zucchini. It was seasoned with soy and served with a little beef (cooked separately).

Zucchini with eggs (1):
I used a small zucchini and a tomato, pan-cooked together with a little olive oil, black pepper, and salt. Then I added eggs, scrambled everything together, and added some cheese at the last minute.

Zucchini omelette (2):
This is a variant on zucchini and eggs. I pan-cooked zucchini, tomato, red onion, and green pepper in olive oil for the filling, with basil, black pepper, and salt for seasoning. The omelette was an ordinary omelette, with the some mozarella and some Munster added just before putting in the veggies and folding the entire thing.

Zucchini salsa:
I finely diced a small zucchini, lots of garlic, some tomatoes, some red onion, and some green pepper. I sauteed the zucchini and garlic in olive oil, which I used more generously than I sometimes do, and added black pepper and salt. Then I added the red onion, green pepper, and tomato, and cooked it all a little more. I think it would taste good without the second cooking, too. I mixed in a healthy dose of lime juice and served with the end of a two-day old baguette, which I sliced into thin rounds and toasted. I put the salsa in a bowl and arranged the toast in a double ring around the outside. It looked colorful and elegant -- at least to my eye -- and surely was one of the more appealing ways I've used up a zucchini, a fading pepper, and a slightly stale baguette end.

• Currently drinking: Hot water with lime and honey

Two minutes before completion, I lost the network connection to my machine on campus. Since I foolishly ran my hour-and-a-half simulation in the foreground, it was terminated when my secure shell session was terminated.

Joy.

Let's try something different for the moment: a mostly-unrewritten entry.

Usually, I write with great pauses between sentences. Sometimes the pauses last so long that I forget what I was writing in the previous sentence, or that I abandon a paragraph -- or an entry -- entirely. At other times, I write the same sentence four or five times, and constantly delete and re-type. I'm picky, and half the time I can't even form something grammatically correct the first time it comes out. Or if I can form something grammatically correct, it's technically incorrect, which is nearly as bad.

I am procrastinating now, though, from -- what else? -- writing. So this seems like a good experiment.

I write here for three reasons, really. The first is the reason that has kept me writing to myself for many years: I forget things. More specifically, I forget the chronological order in which things occur. Well, I sometimes forget other things, too -- like birthdays and people's names and where I put my glasses. But in terms of remembering events, I'm pretty good at keeping odd little details in my memory. I just forget the matrix in which those details should be embedded. And so I have a few notebooks of terse recounts of my days and weeks, which I doubt would be of much use or interest to anyone but me.

The second reason is to communicate with friends and family, which is really most of the set of people reading, I think. If someone else finds it amusing, that's fine, too. And for those arriving at these pages through a search engine: the proper spelling is teetotal, the conventional definition is to abstain completely from alcoholic beverages, and dictionary sites will probably serve you better than this search.

The third reason is to think. I do mathematics with pen or pencil in hand, and the pen is often moving, even when I'm staring into space. I take notes in classes that I find particularly difficult, even if I never look at the notes later. I write summaries of problems that I work on, even if I have no intention of sharing the summaries with anyone else. The act of writing forces ideas into a more concrete form, filters the mental fuzz, and enhances the memory. I can write some pretty incomprehensible garbage when I'm not thinking straight, but it's easy to recognize it as garbage once it's on paper.

This is not to say that I'm deliberately spending my time filling this page full of garbage. It is to say that some of the things I write have more to do with me writing than with you reading.

Even if there are no real meaty thoughts behind them, it's a joy to run fingers over the keyboard. It's almost as much fun as writing with a pen, though the two activities are different and suit different moods. I imagine I might get the same joy from playing a musical instrument, if there were any musical instruments that I played competently.

I'm listening to the radio. I'm waiting for a simulation to finish; it has about forty minutes left, which means that it's more than half finished. Sitting beside me is A Walk in the Woods, with the cover picture of a green forest and a bear's head peeking up over the subtitle bar at the bottom. On the other side is a pile of pages of scrap, intermixed with the marked-up pages of an old draft of the report I'm currently working on -- or avoiding working on, as the case may be. There are so many marks on the borders of the draft that it is hard to tell those pages from the pages of scrap paper. The pile is relatively neat, but I doubt the pages are in the right order, and I'm sure that the pages of the draft are mixed together with the pages of notes. And since I've processed most of the comments in the draft that actually meant anything for more than a minute after I wrote them, the state of disarray is just fine.

I don't think I had a face-to-face conversation for all of the day, unless you count the interaction with the clerk at Barnes and Noble. I talked to Winnie on the phone, of course, but beyond that, I don't think I had any conversations today. For that matter, I haven't had many conversations since the start of the past week. People are out of town, at home and at the office, and so days have been quiet. Suits my mood, it does. Still, I'm glad Winnie visited on Friday, and I'm looking forward to having dinner with her again tomorrow night.

And I'm actually really looking forward to my trip this coming week, even if it's a little bewildering to travel again so soon after I returned from Copenhagen. Well, perhaps it isn't that short a break.

Tap, tip, tap. Perhaps I should return to reading. Or perhaps I should return to editing.

I felt like a walk this afternoon. So I went to Barnes and Noble, where I got the next two Patrick O'Brian books and Bill Bryson's Walk in the Woods. After laughing so hard at the inebriated sloth in O'Brian's H.M.S. Surprise, I thought I would probably read the next in that series first. Instead, I read about the Applachian Trail for a while.

I opened all the windows and both the doors when I returned. It's a fine day, and the breeze passing through feels good.

• Currently drinking: Osymanthus black tea

During a break a little while ago, I found this article on the Bookshelf as Identity. I was reminded of an article a friend sent a while back, entitled The Library of Congress Comes Home. Both articles are about bookshelf organization, though from very different takes. And both concentrate on the topics of the books.

My bookshelves are topically organized only in very broad strokes. Books that have something to do with religion or philosophy mostly go on one shelf -- though that shelf also has my copy of The Smithsonian Book of Books and The Complete Guide to Calligraphy. I would say that this indicates something about my personal pantheon, except that the same shelf has Fermat's Enigma, Stairway Walks in San Francisco, The Pig Who Sang to the Moon, and Worms Eat My Garbage. Further down is a shelf which houses a few history books: From Dawn to Decadence, Africa in History, and The Soong Dynasty are there. So is Autumn Lightning, which is half history (the other half is autobiography). But wedged right next to those books are Kay's Tigana (fantasy), Zinnser's On Writing Well (what it sounds like), Brooks' The Mythical Man Month (software project management), Icke's Force of Symmetry (physics), Asimov's Azazel (humor), and an odd copy of SIAM Review (an applied math journal). Furthermore, Churchill's History of the English Speaking Peoples and Lewis's The Middle East are a couple shelves down; and Herotodus is again on the shelf with philosophy and religion, two books down from the Tao Te Ching and three from Marcus Aurelius.

So what's the correlation? Well, if you took all the books from one of my shelf and put them into a cardboard box, you'd probably find that they packed together pretty well. The philosophy shelf also happens to have a lot of books that are shaped oddly, and didn't fit that well with anything else -- the Book of Books in particular is very tall, and doesn't fit at all onto some shelves. Most of my science fiction fits neatly on the bookshelf by my bed, simply because those books are all paperbacks of roughly the same height, and taller books don't fit well on those shelves.

There's some shuffling over time, of course, as I take a book down for reading or simply for reference, and as I put back books that begin to clutter my desk. And the books in my office are a little more topically organized: mathematical analysis in one place, computer systems in another, mechanics in another, and linear algebra -- well, linear algebra moves about the shelves and about the office, but there's some sort of concentration between the books on technical writing and the books on analysis. Even there, though, I organize by physical shape and by the frequency with which I refer to things before I organize by topic. And it shows: there is no topical reason for the top-shelf mixture of books on statistics, asymptotics, special functions, and other amusements, except that a lot of them are Dover paperbacks with sort of similar shapes.

It's fortunate that my spatial memory is better than my temporal memory, or I'd lose all sense of where my books live. But if you spoke no English and were somehow tasked with finding a place for a stray tome from my collection, I suspect you would manage to find a good place for it. Just be careful if that place is the shelf o' philosophy. You might knock over the origami cat.

Still looking for an old bookmark to a technical paper, I found a bookmark to Nature's debate on open access. Alas, my opinions on the topic are not sufficiently well formulated that I care to write anything about them.

Going through my bookmarks in search of something else, I stumbled across this page of photos of skills found only in China. I think I might be able to sleep atop a chain link fence, too, if sufficiently motivated.

• Currently drinking: Black coffee

As a youngster, I often responded to inquiries about my day with I ate lunch; I had recess; and... um... I've changed in many ways, but my response to such pleasantries has changed little. I know people who can reply smoothly and quickly to such inquiries, and to other social pleasantries; I have not decided if the smoothness of their response comes from some quickness of thought that I lack, or whether some habit or reflex allows these people to handle such routine interactions without any thought.

When I spend a day writing and revising, re-reading papers I've cited, and generally chewing over the presentation of a few technical ideas, I have an even harder time answering social questions. Writing code, sketching calculations, and related pursuits can be wordless things, difficult to express even to someone who asks about them with more than a perfunctory social curiosity. But a day of wordsmithing, perhaps, engenders the opposite problem. It's all too easy to express the words I've been thinking about all day. Do you want to hear why local moment-matching approximations are so attractive for producing reduced models of RF resonators with anchor losses taken into account? Or would you like to hear how to formulate the analogue of Sommerfeld's radiation condition for linear time-harmonic elasticity problems? The answer, of course, is likely a resounding no: the question what's up? is an invitation to a smile and a nod, perhaps, but not to an impromptu lecture, let alone an impromptu research presentation. So I smile, I nod, and these days -- usually -- I keep my impulses in check and stick to safe topics of conversation, like what I had for lunch; at least, that's what I'll do until my mind has had time to warm to some more mutually entertaining topic.

I had New England clam chowder for lunch, and a cup of Russian Caravan tea afterward. And dinner was a scramble of leftovers, combined in a way that called for no particular culinary skill, with some spiced black tea later. Oh, and I spent some time writing, and some time managing my recipes. Or managing my references. Um...

• Currently drinking: Hot water with lime

On my way to a meeting on Thursday afternoon, I was caught in a river of capoieristas walking along Shattuck. I was late, and in a grim temper, and I was not well pleased by the slowness of the crowd. But two women in front of me were practicing samba as they walked, and when one of them stopped so suddenly that I nearly ran into her, she grinned such a cheerful apology that I couldn't help but grin back. I was tempted to skip the meeting altogether, and walk with the crowd to their final destination, to hear the merimbau played and perhaps to see a roda. But I resisted the temptation, and went to my meeting.

On Friday, I walked to school to receive a call from a collaborator. As I walked by the park near my home, I saw two men practicing forms. More specifically, they were practicing one of the forms of a style from southern China which a college acquaintance of mine practiced. I slowed for a moment, watching. The Chinese martial arts can be very graceful, and one of the men was quite smooth; the other had problems with his elbow. While I watched, the more experienced man turned to his neighbor and corrected the position of his elbow, showing how to set it up to cover against a strike to the ribs even as the hand parried a strike toward the head.

Last night, I was deep in H.M.S. Surprise by Patrick O'Brian, and came to a passage involving an inebriated sloth. I laughed until I had to put the book down to catch my breath. In time I recovered, and as I reached to pick up the book, I thought Wouldn't a drunken sloth school of martial arts be grand? Practitioners would learn how to plod slowly along tree branches for a few feet, then fall asleep with one arm and one leg wrapped around a branch, half-dangling from their perch. Advanced exponents would learn to miss their footing and fall artfully in a way that squashed opponents passing below.

I think that the Drunken Sloth style, along with the style of Bread Do, would be a wonderful addition to the mix of Hong Kong action movies. But for longer lasting interest, I'll keep watching the parks and the streets on my way to work.

Death is a conservative sort of fellow. He still rides a pale horse, and does his work with an old-fashioned hand scythe. But with the world as crowded as it is, Death needs some assistance with his busy rounds. Something so that he can quickly be reached if needed, wherever he may be.

Thus, the Grim Beeper.