AT SCHOOL AGAIN
  Optimus woke in the morning, revved his engine long and loud and exhaustily to
shake off the sleepy residue of yet another nostalgic but totally irrelevant
dream world, and started work. He had been connected to a videorecorder during
this dream, something that humans can't do. He realized that perhaps Yablanovski
in Millwrights Department at Smith & Malton's would like a copy of the tape.
  [238] Prowl as usual went to a school in Droitwich to teach computer
programming. He drove into the room, transformed, went behind his table, `knelt'
on his hips which he bent at a right-angle backwards, plugged himself to the
electricity mains to avoid making exhaust indoors, and spoke to the class, who
were by now used to seeing him:
  "That Paul Smith's latest batch of accomplices have been caught and identified
[see 151-160]. Photos of them are on the noticeboard in the corridor. Tell me
about any approaches they may make to you. He now has no gang and no backup, and
his father is on our side and will not back him up, and anything to the contrary
that Paul Smith may say is bluff.
  So much for that. Back to work. Writing a function in `C' to work out square
roots. Jameson, your program works, but why in the name of Iacon's great dome
can't you forget <football>!? (You'll never get into any of those big teams you
harp on, judging by your performance in school sports.) First, retype your
program using ordinary names. Then, in the future you will lose one mark off
your accumulated term total for each football expression that turns up in your
work where it isn't called for. I'll save all your screen displays and display
his effort on them, as an example of what to avoid. That sort of thing is no
good for anyone who wants to develop your program after you, having to sort
through all that irrelevant stale exhaust and not a comment anywhere in the
text!?".
   The class laughed, for this appeared on their terminal screens:-
   OK: SLIST JAMESON>LEEDS.CC
 main(){double Burnley,United,Tottenham; int West_Ham;
 Wembley: printf("value?(0=stop)"); West_Ham=scanf("%le",&Burnley);
    if(West_Ham<1?1:Burnley<0) {puts("FOUL!"); goto Wembley; }
    if(Burnley==0) exit(0); United=Burnley;
 Maine_Road: Tottenham=(United+Burnley/United)/2;
    if(fabs((United-Tottenham)/United>1e-6) {
       United=Tottenham; goto Maine_Road; }
    printf("GOAL! sqrt(%e)=%e\n",Burnley,Tottenham); goto Wembley; }
  Prowl continued: "Most of you test and jump back in each repeat. This takes a
long time for very big or very small values. The right way is this: Take
argument. Split binary mantissa from exponent, with mantissa between half and 1.
Halve the exponent. Reassemble. The value will now be wrong by a factor of no
more than sqrt(2.0). Then iterate a fixed number of times, which is quicker in
this method than testing each time, since in this method rate of convergence
depends only on proportional error.".
 OK: SLIST PROWL>SQRT.CC
 double sqrt(a) double a; {double x,mantissa; int exponent;
    flp_unpack{a,&mantissa,&exponent); x=flp_pack(mantissa,exponent/2);
    /* x is now no further than a factor of sqrt(2.0) away from correct */
    if(x==0) return 0; if(x<0) {puts("error, sqrt -ve"); exit(1); }
    #define step (x=(x+a/x)/2)
    step; step; step; step; step; step; step;
    /* as using a counter to count how many steps, takes time */
    /* more or fewer steps according to how many bits in the mantissa in the
    computer used */
    #undef step
    return x; }
  "Huh!" Jameson thought tiredly, "x=(oldx+a/oldx)/2; if(fabs((x-oldx) ...
Life's not worth living without football! That Jack Brown and that tin can Prowl
that he lives with since his parents - that matter [ref 124-134] - they're both
alike! If football starts on the telly, they switch off or switch over! `22
louts fighting over a ball should be', Jack called it!". Then his terminal
beeped and flashed and its screen cleared, and this message appeared on it:-
  "MESSAGE FROM <DROITWICH>FORM3>PROWL TO <DROITWICH>FORM3>JAMESON
  Message from Mr.Jackson (History teacher):-
  `You were asked for an essay on the United Kingdom (= Great Britain), but you
submitted an essay on Leeds United and Manchester United football teams. An
immature piece of work full of uncritical hero-worship, at that! You should know
by now what `United Kingdom' means, never your usual one-track mind! You lose 30
accumulated marks, and you will see the headmaster next break period.'. Type
`SAY PROWL, YES SIR' to say that you've read this."
  "Agh!" Jameson thought, "Wirebrain Prowl wired to the phone, gets messages
without me knowing it! Can't they call Britain `Britain' and not be confusing?
Everybody knows what `United' is!".
  [239] "Right, Jameson?" said Prowl, "From now on, football stays at home. (All
this studying of the big teams has done you no good, judging by what a hopeless
rabbit the games master says you are in football in school sports.)".
  "OK, OK, tin can with horns on. You're like the rest. I try to put a bit of
interest into things, and it's always wrong. School's a yawn." Jameson thought
tiredly, then said "Why write `step;' all those times? Why not in a loop?".
  Prowl replied: "Because it won't take over seven steps to get the result as
accurate as can be stored, in this program, on this computer, and if I wrote
`for(i=1;i<=7;i++) x=(x+a/x)/2;', each time round the computer's got to add 1 to
`i', then test and jump. All this takes time, and as square roots are needed a
lot, it's quicker to write the repeats in full, it saves much time over the
amount of times in a day that square roots are wanted. And a register is tied up
acting as the counter `i'. Oh, another thing. The last algebra problem, most of
you did this:- x*x + x*y + y*y = 7 & x*x - x*y + y*y = 3; so x*x + y*y = 5 &
x*x*y*y=4; so x*x = 1 & y*y = 4; so x = +- 1 & y = +- 2. This means: x = 1 & y =
2, right; x = - 1 & y = - 2, right; x = 1 & y = - 2, wrong; x = - 1 & y = 2,
wrong. It's thrown up two wrong answers as well as two right answers. You tend
to get that sort of thing with simultaneous quadratics (or higher powers),
although no algebra mistakes. The wrong answers are called `ghost solutions',
the only way to spot them is to ...".
  "Put on an `ecto-visor'." Jameson interrupted, reflecting that if Prowl could
scoff at football ...
  "Ghost solutions?" said another boy, "Get Captain Blowtorch to sort them out
with his `proton pack'! next time he comes to teach metalworking.".
  "Oops!" Prowl thought as the class sang the `Ghostbusters' song in chorus. "Oh
help. Ever since that movie `Ghostbusters', another excuse for time-wasting
sillyness when certain things are mentioned. Every so often some word gets a new
meaning or atmosphere, like the word `transformer' got in 1984." he thought,
then revved his engine loudly to call for silence and said "Quiet! No! <You> do
the `ghostbusting', by backchecking with the original equations. In this case,
the ghost solutions arose when you eliminated or squared the x*y term, which
correlated the signs of x and y. And, once more, what <Mr.Malton>, to give him
his proper name, has is an oxyacetylene torch with cylinders worn on his back.
There's no such thing as a real working `proton pack' anyway, any more than real
rayguns. He'll help at your next lesson, which is metalworking. And the biology
master tells me he's had the same sillyness from you now that the word
`ectoplasm' has turned up in its proper sense of `the transparent outside layer
of a protozoan cell'. No more of this!". "And of that fascination with
`Transformers', I am one end result, when James Wernicke got so desperate for
the fictional Optimus character that he made a real Optimus, who made others
including me.", he thought as the boys went to their next lesson.
  Mr.Malton got out of his van and walked towards the school metalworking
building's door, impressive in his helmet with visor, thick overalls, heavy
boots, chest pouch for tools, and blowtorch cylinders strapped to his back. From
the cylinder tops the gas lines looped over his shoulders to a torch head in a
holster on his chest. The pressure gauges on the cylinder tops showing over his
shoulders added to the mechanical appearance. He led an Alsatian. "Mr.Malton?"
said a policeman approaching him with another man.
  "Yes, that's me. Will you be long? There's a class of children waiting for me
here." said Mr.Malton annoyedly.
  "This is Mr.Dumesnil, Atomic Energy Authority." said the policeman, "Would you
care to go in my car back to your works? A rather serious matter about some of
your equipment - reports of particle beam experiments in attempts to copy
fiction, like the way that Wernicke's real Transformers arose.".
  In Mr.Malton's mind the familiar vague disquiet arose, but vanished when the
policeman said "Atomic". Mr.Malton, wondering yet again what what back area of
his brain was suspecting about what, and what now had arisen, replied: "Sorry,
but not till you tell me more about it! I'm in no particle beam matters. The
only thing radioactive or subatomic I've got is a few radioisotope pellets to
look for flaws in metal and bad welds. You must have bad informants or malicious
false reports. What is all this!?".
  "I thought you'd save me having to get a warrant for arrest and search." said
the policeman.
  "If you must know," said Mr.Dumesnil, not caring to come too close to
Mr.Malton's take-it-anywhere backpack-blowtorch and ideas of what a gang of
roughs equipped with them might use them for, "it's backpack particle beam
devices, almost certainly inadequately shielded except on the side towards the
wearer's back to save bulk and weight, and the bystanders get dosed with
radiation!".
  [240] Mr.Malton laughed loudly and said angrily: "They wouldn't be called
`proton packs'!? Look no further! I'm wearing one, or what local children keep
playing at thinking is one! They keep calling my backpack blowtorch a `proton
pack' out of `Ghostbusters', and different people tell different people about
this, and the story gets distorted, and some stupid official takes it as
serious! I'm sorry your time's been wasted. Oh well, go get your warrant, and
while it's coming, find your informant and track his source of information to
its actual start! Some idiot mishearing someone describing children's clownings
about and calling things wrong names as slang or in play! Then summons <him> for
wasting your time! I've - got - no - atomic - particle - devices! I leave that
sort of thing to the UKAEA! And it'd take several times all my capital to set up
that sort of experiment! Next time `do your homework'! I'm a mechanical
engineering manufacturer, I leave atomic stuff to other people!".
  "I thought it sounded unlikely, Mr.Malton in something like that, but you
insisted. I know him, you'll find nothing there." said the policeman as he went
away with Mr.Dumesnil.
  "And if it turns out that I <have> been idiotted by some silly joke or rumour
taken as true - like about those group scuba diver disappearances that have been
in the newspapers - too many scuba divers mucking about near coastal atomic
power station intakes and outfalls and suchlike ..." Mr.Dumesnil thought sourly.
  "Now to get to 5th form metalworking! backpack particle beamers!? What
accusation next?, some people." Mr.Malton thought, "Anyway, those two craft I'm
making for the Navy are quite enough for me, without mucking about with atomic
stuff.".
  As Mr.Malton reached the door, he heard Mr.Allington the teacher say to the
class: "... before Mr.Malton comes, I better tell you that we're in another
`don't leave things about' period. That machine we had delivered, it was left
sheeted, and the sheet disappeared overnight. Also, someone's been pinching
things and messing about round gardens and sheds round here at night. And the
caretaker's bicycle's vanished. Do you know anything about this?". Nobody
answered. Mr.Malton went in and started to demonstrate the various uses of
oxyacetylene blowtorches.
  A boy used a blowtorch with fullsized cylinders in a cylinder trolley to cut a
piece of steel. Another boy, Peter, started to tell him "Joe! Look at this I've
g ...", but broke off with an "ouch" as Mr.Malton prodded Peter with a length of
steel rod and said:
  "Idiot! Don't distract people using blowtorches!".
  Mr.Allington, noticing a lack of something, said to a boy who came from behind
a machine: "Demyanchuk! Where's your school uniform? You coming in a boiler suit
like a workman's son. Enough of `can't afford' and suchlike excuses. And
<where's your tie>!?".
  "It's in the wash." said Demyanchuk, "Dad says I'm to wear overalls to
metalworking class. He says loose jacket tails and fronts and ties may get
caught in machinery. And oil and coolant on my shirt may cause `industrial
dermatitis'. He works in a factory.".
  "Oh. Again the laundry's convenience comes before school, and parents
countermanding school rules." said Mr.Allington irritatedly.
  "We've had this before." said Mr.Malton, "I'm sorry, but I agree with him and
his parents. Loose flapping clothes cause countless industrial accidents, and
neckties are among the worst! Near machines, your necktie goes in your pocket!".
  "Agh!" said Mr.Allington, "Things in the wash. Boys coming to games in wrong
clothes, `Mum was going to wash it on Monday, but she was cooking all day for
visitors.', and suchlike. Now I get countermanded over uniform discipline with a
lot of industrial factory yard language. This isn't a factory, it's a school.".
  "Sorry," said Mr.Malton, "but by law this building is a factory, since these
machines are in it, and the usual safety precautions apply. Ties in pockets. Get
overalls for them. They wear special clothes for games, don't they?".
  "Uh! Orders from here, orders from there, nothing's one's own any more."
Mr.Allington complained.
  "Oh, and that machine that was left out, why isn't it sheeted?" Mr.Malton
asked.
  "Someone stole the sheet in the night. And other things have happened. Someone
messed about round the storeroom, but the dog barked, and someone heard someone
running away, two nights ago." said Mr.Allington.
  "Please sir," a boy said, "someone keeps taking cartons from where the cook
puts them out, and she keeps finding her rubbish bins tipped out and thrown
about, and they're too heavy for it to be foxes.".
  "And Prime Bookshops (no connection with Prowl's boss) says they delivered a
parcel of books, nobody in, so they left them, idiot trick when there's thieves
about, but we never found the parcel." said Mr.Allington.
  This seemed somehow familiar to Mr.Malton, but he could do nothing about it
now. "Let's get back to metalworking." he said.
  As Higgins was concentrating on getting a radius of a piece of steel which he
was turning on a metalworking lathe to a correct 2.784 centimetres as Mr.Malton
had told him to, his school tie gradually slid upwards out of his jacket as his
shoulders moved about. It came out and hung loose. A draught from a door as
someone left the room caught the tie, and it wrapped round the rotating
workpiece. Higgins made strangled noises and pulled and scrabbled frantically in
vain for the lathe's OFF button as his throat was pulled towards fast rotating
steel parts. Suddenly a sheath knife flashed in from the side and only just
missed his chin as it cut the tie off short. Higgins, freed, recoiled backwards
and fell against a wall, then stood, feeling wobbly-legged and shocked.
  "Is that a dagger I see before me?" he quoted from `Macbeth' to Ellison, who
still held the knife, "Phew! Lucky you had it on you!".
  "Clumsy ass!" Mr.Allington shouted, glaring at Higgins's scared face and the
cut stump of his tie, "<Watch> where your clothes are! Go to the headmaster now!
Then not back here without a new tie!".
  "I was going to take it off, like Mr.Malton said, but I did before and you
said you'd punish if anybody took his tie off `looking untidy' again." Higgins
pleaded.
  "<And> you, Ellison! What are you doing with a <knife>! on you? You go to the
headmaster also!" said Mr.Allington.
  In Ellison's mind, something snapped. "Lucky I had it!" he said angrily, then
with words and defiance that his normally peaceable mouth had never uttered
before, although he had heard them used sometimes: "You *@&^ martinet over
^&^%&$ silly neckties! I @#!@ won't!", pulling his own school tie off and
trampling it on the oil-stained concrete floor, feeling shocked at his own
actions.
  "No. Go and lie down on that packing in the alcove, to get over the shock!"
Mr.Malton countermanded to Higgins.
  "Right!" said Mr.Allington to Ellison, "Now it's the cane, that filthy
mouthful of working-class abuse to your betters over the school tie and the
wearing of it!".
  "No, it isn't the cane, or I'll cane you, or worse, you arrogant wimp risking
lives for silly dress-rules." Mr.Malton shouted to Mr.Allington, "He saves a
friend's life and you try to punish him for it! I'm talking of Higgins's throat
nearly being ripped out, `inquest' and `coroner' and all that, not bits of
decorative cloth! What do you expect Ellison to do and say, if he's got any
spirit at all!? What did you expect to happen some time!? Of course Higgins
couldn't concentrate fully on <both> his work <and> on where loose personal
ornaments are! Right! Nothing to the head about Elliott, and no punishments, and
if so, I won't go to the factories inspector about you ordering them to
dangerous clothes wearing near machines. And from now on, in metalworking: Ties
in pockets! Fasten all jacket buttons, regardless of fashion and school customs!
All watches and jewellery in pockets also! And as soon as possible, get
overalls!".
  [242] "OK! OK! `Captain Blowtorch', 16 stone and all of it muscle from carting
that kit about all day." said Mr.Allington, rubbing his head in distraction,
"Nothing's anyone's own any more, not even school metalworking class. Another
forced exception to put a pickaxe handle through discipline over smartness and
proper dress! The idea of my class marching about in factory safety boots (which
you'll be wanting them to wear next, I suppose) and overalls and no ties (and
bright coloured plastic helmets instead of caps, I suppose, also) like a bunch
of your workmen clocking-on - OK! You win! Again the barbarians break in on the
orderly Rome of learning and school discipline and appearance!".
  The class ended. Mr.Malton went out, still with his bulky oxygen and acetylene
cylinders strapped to his back. "So much for neckties among machines, and
suchlike `danger dangles'." he thought as his heavy hobnailed marching tread
crossed the playground. He went behind the gym to a water tank support that the
headmaster had told him needed repair. Behind the gym it was damp from the shade
of several trees. "Come <on>, Billy, heel!" he said to his Alsatian as it
stopped to use one of them. He looked at the water tank support. "No wonder it's
so rusty, all this damp. It'll need a lot of work on it." he thought, "Someone's
been sneaking round here to smoke and left the evidence littered about. I better
tell the headmaster. Smoking does nobody any good except tobacconists.".