Chapter 8: Hex

Samuel Vimes strode across the grounds of the Unseen University towards the main gate. He stopped striding. To his right sat the High-Energy Magic Building. He pondered for a moment and went in.

It didn't take long to locate the massive Hex computer. A young lady was seated at the controls. She was absent-mindedly stroking the back of a cat which lay beside her.

"Excuse me, miss."

The young lady turned around. "Stibbons, actually. Professor Ponder Stibbons. And you are Samuel Vimes, if I remember correctly."

"You know me?"

"Back in the days before I came to school here, and before you, um, got respectable, me and my mates used to throw rocks at you and call you 'rummy'. Don't you remember?" He continued to pet his cat.

Sam shook his head. "Not from those days, no." He came forward. "So this is the celebrated Hex computer." He looked at the tag: Anthill Inside.

"Oh yes, we're quite proud of it."

"Tell me about it."

"I, uh, don't know if I should."

"Hey, if you can't trust a policeman." Sam grinned.

Young Professor Stibbons looked down and asked the cat, "What do you think?" When she didn't answer, he shrugged and replied. "Hex's main purpose is to analyze spells, to see if there are simpler 'meta-spells' underlying them, and to help me with my study of 'invisible writings', by running the spells used to bring the writings into existence. These spells must be cast rapidly, and each one can only be used once before the universe notices they shouldn't work.

"It began as a complex network of glass tubes, containing ants. I used punched cards to control which tubes the ants could crawl through, thus enabling Hex to perform simple mathematical functions.

"However, Hex has developed the habit of constantly reinventing itself. Part of it is now clockwork, which interfaces with the ant farm via a paternoster the ants can ride on to turn a significant cogwheel. Indeed, Hex contains several things that nobody can remember installing. There is, for example, a Howondaland window mouse(fn1) named Lisa. No one knows what practical use a mouse would have for a computer, but the one time we managed to get her out, Hex simply shut down and refused to function."

Sam interrupted. "You almost blew up the Discworld with this thing, didn't you?"

"What? With Hex? No."

"With the Thaumic reactor, which it controls."

"Well, blow up the Discworld is a bit of an exaggeration, isn't it sir? I mean, up in Loko where things went as bad as they possible could, the resulting explosion only created a very deep valley and a massive mountain range surrounding it."

"But how much ambient magic was there in Uberwald? Especially when you compare it to the amount of ambient magic here in the Unseen University. Yes, if you were to ever overload your thaumic reactor here in the middle of all this magic, I expect the blast would not cease until the Discworld were reduced to a giant chunk of roasted turtle meat."

Ponder Stibbons squirmed. "Hasn't happened yet, sir."

dQC

Leonard of Quirm slowly turned the nautilus shell over and over in his hands. "Octorine algebra," he muttered.

The Patrician sat with his legs crossed, sipping on a cup of tea. "I beg your pardon?"

The mathematician waved at his query. "Oh, it's a higher form of mathematics, dealing with things like imaginary numbers and cotillions. It's really quite useless, except when talking about distant relatives, string theory, and quantum."

"Quantum?" the Patrician echoed nervously.

"My good man, don't worry. No quantum here, no sir. Why, take a look at this nautilus shell, for example. It spirals around and around down to a point, which of course, has a height of zero and a width of zero, but . . ." he turned the shell ninety degrees, ". . . it has an actual depth. Thus, it's not a true point, but a string."

The Patrician raised an eyebrow. "Isn't string theory pretty much the same things as quantum logic?"

"No sir, not at all! They're completely different. Well, maybe not completely. Actually, they're quite close. Pretty much the same thing, I guess."
"Quantum." The Patrician's voice was not happy.

"I think what the killer was after was a string of quanta."

"Whatever for?"

"That's what doesn't make any sense. For such a string of quanta to be of any use whatsoever, the killer would need access to a supercomputer, a thaumic reactor, and of course, to softlore code."

"Excuse me, Leonard. Softlore code?"

"Yes. Softlore is the instruction code which controls a computer. For example, once upon a time, for a bit of a giggle, I wrote instructions which would tell Hex how to destroy the Discworld."

"Really? I see. And do you still have that code?"
"Oh yes, it's right here." Leonard of Quirm turned around and began searching through the loose papers which littered his desk. After a while, he shook his head and gave up. "Growing old is a terrible thing. I could have sworn that I just saw that code here a couple of days ago. Now, where could I have put it?"

ENDNOTES:

1 If Lewis Carroll can have a dormouse in his tales of Wonderland, then I am certainly entitled to a Howondaland window mouse.