The Trestle

One summer, D. and I stayed at Swarthmore to do research work for Professor G. in the math department. Another professor was traveling that summer and she let us stay at her home in Wallingford in return for keeping her two cats happily in kibble. One cat was rather ordinary in its disdain for humans, but I remember the other was positively canine in its affection and willingness to please others. Also, it once leaped to catch a moth and fell behind a chest where it got wedged and mewed pitifully, wanting rescuing. To this day, that remains the most clumsy and ungainly act I’ve ever witnessed by a cat.

Most days, we usually commuted to the computer lab by bicycle, a fairly hazardous enterprise on some of those heavily-commuted, potholed roads. But one day I got caught up in completing a particular algorithm and worked late, with a pizza and several napkins to keep my greasy fingerprints off the keyboard. By the time I was ready to go home, it was too dark to bike, and the last outbound train had already left. I decided to walk home, taking the shortcut on the railroad tracks over the Crum Creek trestle.

It was a clear night. Crum Woods was empty of people, summer-warm, and full of crickets singing. I walked along the railroad tracks, planning algorithms in my head and trying to stay upright on the balance beam of one rail. I remember the crunch of gravel whenever I slipped off, startlingly loud like a cough drop wrapper in a darkened auditorium.

When I reached the trestle, it was a hard to see across, because the moisture of the cold creek water was condensing and turning to fog as it rose, but I didn’t think twice about crossing. I had missed the last outbound train, and though I thought a later inbound train unlikely, there were two sets of tracks, so I could get out of the way if necessary.

Halfway across, tunelessly singing Cat Stevens in my croaking tenor, my attention was diverted by a glow on the horizon, like a distance forest fire, but white. It could only be a train approaching in the distance, out of sight behind the sweep of woods. I was twenty-one, too young to seriously consider mortality, and I wanted to see this, so I gingerly stepped across to the outbound track to wait for it to pass. I say “gingerly,” because there were gaps between the railroad ties through which one could drop a stone to the creek a hundred feet below. The gaps were not large enough to admit my entire body, so I would not have plummeted through, but a wrong step might have sunk my leg up to the groin.

The train seemed to take a long time to arrive, clacking along with gravid determination. But I was mistaken by the scale of it. It appeared around the corner out of the trees on the far bank, like a rampaging bull, enormous, heavy, and very powerful up close. The halogen light on front of the engine shattered against the fog, and the entire valley, the very air, seemed to burn with a magnesium fire, and I in the middle of it, unconsumed. I could see nothing, not even my hands. Every direction I looked, even up and down, the world has turned to a brightly glowing swirl of white light. But that wasn’t all. When the engine was less than 100 feet away from me, the engineer, perhaps suddenly aware of my presence for the first time, pulled and held the “whistle,” a rather antiquated term for that high-decibel horn.

The sound erased my brain. “Too loud to think” doesn’t adequately describe it. The sheer violence of that noise drove everything from my mind, leaving no room for a thought to interpose itself. I felt my heart thumping in my chest, the blood pounding in my ears, but I could hear neither until long after the crescendo of the passing horn was replaced by the comparatively gentle screech and clacking of the metal wheels on the other track, and the groaning of the wooden trestle timbers beneath my feet. I remember feeling very alive at that moment, trembling, my senses assaulted, all my hairs on end, and a new found faith in my utter insignificance, crushable as a bug.

When the train finished crossing, and I heard its brakes from around the far curve settling into the Swarthmore station, it was though my body was finally released from some spell. I moved suddenly, picking my way across the trestle as quickly as I dared and high tailing it home before any uniformed agents of the SEPTA system could track me down.

Help Me Solve a Puzzle!

Here is a puzzle for you mathematical and/or electrical people.

Harry has a basement room with two overhead lights in it. For some reason, these lights are not on the same switch.

One light, which we will call Tom, is a simple, easy-going light. It turns on and off with a single switch in the basement.

The other light, Cristobel, is more complicated. There is a separate switch in the basement AND at the top of the stairs. Either of these two switches will toggle Cristobel on and off (this is known as a three way switch).

Got it? One switch upstairs toggles Cristobel on and off. Two switches downstairs in the same box. One toggles Cristobel, the other toggles Tom.

Harry’s children are afraid of the dark. They also know they are supposed to turn off lights when they leave a room. When they go down to the basement, they turn on all the lights, but when they have finished playing in the basement, they forget to turn off Tom. They don’t touch the downstairs switches. They dutifully climb the stairs and turn off the switch at the top of the stairs. This turns off Cristobel, but it leaves Tom burning, sometimes for days, wasting electricity. No amount of reminders from Harry seems to stick, so that every time Harry walks downstairs to do laundry, he finds Tom burning and “PING” another hair on his head turns gray and falls off. Harry’s hair are an endangered species, and he would like to save what little remains.

So one day a new light bulb turned on, this time over Harry’s balding head. “What if I just rewire the switches in the downstairs box so both bulbs run off the same three way switch?” thought Harry. But after working on it for an hour, half of which was spent scratching his head and turning on and off breakers and carefully bending stiff wires with pliers, he has pretty much concluded it is impossible. At least, it is impossible only by rewiring the downstairs switch box. Actually, he would be happy if both Tom and Cristobel only toggle off the light switch at the top of the stairs, bypassing the downstairs switches completely. What he does NOT want to do is snake wires through the wall.

Is he right? Is it impossible?

Here are the details. There are five wires in the downstairs switch box: A, B, C, D, and E.

If the upstairs switch is flipped up, and you connect A and C, Cristobel turns on.
If the upstairs switch is flipped down, and you connect D and C, Cristobel turns on.
If you connect B and C, then Tom turns on no matter which way the upstairs switch is flipped.
No other combination will make a light go on.

The astute reading will observe that E apparently serves no function. I am guessing E is a ground wire, but I’m not sure. This is an old house with old wires all with black casing, and I’m not sure they did grounding back in the day.

Scrabble is a math game

One of the really nice things about Dawn (my wife) is that she can’t remember the punch line of a joke, no matter how many times she’s heard it.

Imagine a large, informal social gathering with more people than can comfortably fit in the kitchen alone. Somewhere near a heating source or close to the table laden with food, you’ll find Dawn and myself and eight or so people. Dawn and I are the ones with the root beer and cookies. Eventually, inevitably, as the sun must set each evening, someone will unwittingly make The Straight Line.  “Oh, yes,” I say, clearing my throat, “in fact …”

At this point half of those eight people will recognize that Harry is about to tell The Joke. Again. These astute listeners will suddenly see a person across the room they must speak with immediately. Or they find their glass needs refilling, having just spilled it down their own shirt. But the remaining hapless souls, genteel and polite deer in the headlights, are frozen in place. Dawn is one of them. As the joke uncoils and understanding of the dangers dawns, every facial expression slowly rearranges and locks into a defensive, smiling grimace, braced for the full-frontal punch line. Except for Dawn.  Her eyebrows furrow. Her tongue sticks slightly out one side of her mouth firmly wedged between her teeth. When the hateful punch line is delivered of my mouth, they all flinch, and then nod and smile knowingly with the best manners of the well bred. Except Dawn. She laughs. A real laugh. She’s heard the joke a hundred times, and she still finds it funny.

I married the right woman.

This miraculous trait of hers extends to other realms. Lately I discovered it includes the game Scrabble. When the grandparents, uncles, aunts, and cousins converge from the four compass points to meet at a cabin or beach rental for some holiday, after we have processed more carbohydrates than an ethanol Hummer, dutifully followed with the latest seasonal sweetmeats from the Disney mill, we stay up until the wee hours playing Scrabble. People rotate in and out of The Game, taking turns putting children to bed, washing dishes, or  finishing up the birthday cake; it is always near enough someone’s birthday at these gatherings.

Dawn loves Scrabble, but she can’t seem to win. I can beat her easily, though her vocabulary, counting medical and biological terms, is at least three times as large as mine. Because she can’t seem to understand that it is not really a word game. It is a math game. You can beat anyone if you know a sufficient number of short words (including all the two-letter words published in the Scrabble instructions) AND if you pay attention to those little colored squares on the board. Dawn thinks they are decoration.

She has managed to start our last three games with six letter words and can come up with tricks like adding “ous” to my “hide” but she doesn’t get many points for it. Whereas I will put down an S and an X, forming two words across and one down with the X on a triple letter score, thus getting 55 points. Count ’em – fifty-five! That’s an average of 27.5 points per letter! You see, it’s a math game.

By the way, the word was “SIX,” ok? Honestly, you people.

I think she’s finally catching on though, so I need to distract her. I suggested we start a new version of Scrabble called SciFi/Fantasy scrabble. You can form any word as long as it appears in some science fiction or fantasy novel or story. Words such as “orc,” “muggle,” or even “tardis” count, if the purists will allow that Tardis has graduated in the lexicon from acronym to full-fledged word, much like the English word “tip” supposedly coming from “to insure promptness”. However, I would still insist that proper nouns are illegal. So even though one could truly rack up points with it, however tempting it might be, one could not use “Eryx” from Lovecraft’s “In the Walls of Eryx.” Nor could one empty the tray with “Ni” (as in, “The knights who say…”). I think that will keep her mind off those little, decorative, colored squares for several months.