"It is invaluable to have a friend who is always wrong. Carefully guard that friend, especially from the truth." - Lucius Malfoy



"You wanted practical exercises," Harry said to the rest of the Bayesian Conspiracy, who stood in the center of the modified Muggle Studies lecture hall. They'd quickly settled back in after the first day of classes. Chairs from the center of the room had been moved aside. Giant white boards covered the front and side walls. The front wall showed a map of an island, some waters, and surrounding land. Brooms of various colours were flying slowly across the map as if drawn and erased by an elegant calligrapher. Small ships bobbed slightly in the center of the map, wavy lines indicating water. Extensive listings slowly scrolled up along the side walls, like an accountant's ledger. Each row listed a number, besides a picture of a broom and then a row of relevant information – how long that broom had been seen, it's location, heading, and the like.

Above the main map was a digital clock, large red numbers assaulting Draco's eyes: 20:01:45, 46, 47...

"Welcome to the Bludger, a Skysweeper class." said Professor Asimov. "A Muggle warship specializing in anti-aircraft operations. This room simulates the bridge – the heart of operations – although allowances have been made to translate the information to something you'd recognize."

Hermione walked up to the front wall. "I've seen this map before. On TV." Harry went over and talked to her in quiet words, Draco couldn't hear them, but saw Hermione shake her head. Professor Asimov was speaking.

"These walls would be computer generated readouts of all aircraft, er, broom traffic in the local area. The big ship in the center of the map is your ship. Compared to brooms, it's quite slow, and barely moves. The small red circle is your area of vulnerability. Any enemy broom that gets within that circle could attack your ship."

"What about the larger circles," asked Blaise.

"The medium circle shows the area you can be reasonably confident you are seeing the truth. Beyond that circle your radar – Muggle scrying technology – is less reliable. You may be missing some brooms. The outer circle is the maximum range. You can't see any broom past that unless they are actively telling you where they are. Oh, your radar is also less efficient against brooms that are flying over land, as they may be able to hide."

Harry Potter had finished his discussion with Hermione and continued the lesson.

"Brooms are color coded. Is anyone here color blind? OK, good. Green brooms are friendly. Red brooms are enemy. Grey brooms are unarmed. All brooms appear the same size on this screen, but Grey Brooms are sky buses carrying people and not weapons. Yellow brooms are unknown. They could be anything. A broom with a color and a question mark is presumed to be that color, but not verified."

Neville nodded. "What are those symbols on the land?"

"These," said Harry, pointing to a few crossed lines, "are airports. Airplanes take off and land there. Unlike brooms, which can be used anywhere, planes need specialized facilities. Those you can trust, they take years to build, you know exactly where they are, even if they aren't inside your radar range. These little ship icons represent ships, of course. Same color scheme. Each green ship has it's own red circle."

There were a few desks located along the front of the room, and Harry waved to them.

"Each station has a smaller display, like Professor Quirrell used in his lectures. You can point your wand at the map and bring up information. Be sure you are pointing at the right broom, the simulation doesn't read minds. Or you can use the number and enter it into the keypad. If you look carefully, the map numbers everything so you can talk about it and be sure you are talking about the same broom. Friendly ships and brooms have names as well."

"This is complicated," said Gregory.

Harry nodded. "Battles are. Air battles in particular, since things move so fast. But that's just the technical side. The real issue, and I know that Professor Lockhart has started to cover this, is that you have objectives in any battle. Here your primary objective is to keep your ship safe. And any other green ships that may be around. If a red broom gets too close it may attack. Technically, this isn't your war, there are actually a few different red sides, but for us we'll just consider them one enemy. Your ship is also vulnerable to other ships, all of it's weapons are anti-broom, but others ships fight red ships. So your main issue to figure out the color of each broom. A few of the stations are specialized."

Harry pointed to the desk just off center.

"The main Communications lets you talk to other green forces. You can't talk to green brooms directly, but the other ships will relay any requests. We, uh, haven't fully automated this simulation so you'll just talk to me and I'll adjust the simulation."

Professor Asimov stood next to a large desk off to the side. Apart from a monitor it also had a big red button, underneath glass "The weapon station controls attacks against a broom. There's only one weapon station. Because of the political situation, you shouldn't fire on a broom unless necessary. Even targeting a broom without firing is a hostile act, so try not to do it. The other stations let you inspect the main board in more detail, and have a variety of functions."

"How do we steer the ship," asked Neville.

Harry shook his head. "You don't. Use communications to talk to the people who steer the ship. They handle the naval aspect. You patrol the skies."

The first five minutes went smoothly. They'd elected Daphne general. She didn't sit at any station, just acted as the central decision maker. A year and a half of battles made it obvious to everyone that there would be too much cross talk without someone clearly in charge who didn't have to watch for anything in particular.

20:16:05.

At first, the simulation showed only green brooms. Then a Grey flew towards the ship, appearing at the northern airfield.

Draco pointed his wand at it, and the details came up on his monitor. Commercial flight, on expected path and scheduled 20:15 takeoff, routine, confirmed. Draco shifted his attention back to the map. He was responsible for the area to the north of the ship while Neville watched the south. Two red brooms, question marks tilted besides them, appeared next to the north west airbase and were heading towards the ship.

"Two maybe reds heading towards us!" Draco said, but everyone had seen them.

"How do we know they may be reds?" Daphne asked. "I mean, technically. I can see the map marks them that way."

Professor Asimov answered. "The map makes some assumptions. Those came from an enemy airport too small for commercial airliners, so they are presumed to be red military brooms. The computer marks them with question marks, to let you know it is guessing."

The brooms were closing in fast. Blaise - sitting in the communications station - started talking quietly to Harry, getting information or making requests. Draco couldn't make it out. Three green brooms changed direction to intercept the red brooms and a minute later, the question marks disappeared. It was hard to see on the main map, but Draco's monitor showed a closeup. He could see the individual pencil strokes of each brooms tail.

"Definitely enemies!" Draco shouted.

"Hermione, shield against them," Daphne ordered.

Hermione raised the shields. The two brooms practically on top of each other, she could defend against both. Draco saw them start to break apart, one heading more easterly and the other more to the south. Draco started to say something, but Hermione spoke up.

"They are splitting up, I can't shield both of them for much longer."

Draco looked at the map legend and pointed his wand to "Timer and made a few selections." His screen pulled up a countdown timer. "Broom 1147 will cross the red circle in 45 seconds. Broom 1583 hits in 60."

Daphne considered for a second, or maybe two. "Hermione, shield 1583. Gregory, target 1147."

"Shielding 1583," said Hermione.

"Targeting 1147," Gregory said as she finished.

A few seconds later both planes reversed directions and headed back towards their airbase. Draco nodded.

"Green brooms are following them home," said Blaise. "If they turn around, Green brooms will shoot them down for us." The two red brooms disappeared from the screen.

"They vanished!" Draco yelped.

"Oh," Harry said, "That means they aren't your problem any more. Green brooms are watching them. So they aren't relevant anymore. I'll admit it's somewhat confusing. Would you rather that the map show them?"

A small discussion broke out when Neville shouted. "Five yellows from the south! They are heading towards the Snitch."

Draco looked at the main map. The Snitch was a friendly ship almost due west of them. Two groups of planes had taken off, two from the field directly south of the Bludger, three from the field to the southwest.

"Blaise, tell the Snitch to move towards us and have our captain close," Daphne said calmly. "Draco, help identify those planes starting from the West, Neville, start from the east...Gregory, target the first plane to turn red!"

"They might not be in our weapons range until too late!" Gregory said.

"Tell the Snitch to head to the northeast! That may give us a bit more time. And where the hell are our brooms?" Daphne said, causing Professor Asimov to blink a few times, then smile.

Draco pointed his wand to the westmost broom, 1954. You had to point to the big screen, the little screens wouldn't register the movement until you'd selected a target. After that, it worked OK. That's just the way the equipment works, Harry had said, shrugging. Muggle technology has it's own rules. He'd actually explained that he'd translated it, so that the effect was the same. You had to pay careful attention or you could accidentally focus on the wrong broom. Draco realized that 1954 wasn't the west most broom, his aim had been off, but he sent out the challenge command. Faster to do it out of order than to do it in the right order. A moment later 1954 flicked red. He aimed at the actual western broom 1205, and sent out the challenge. No harm done. There was no rhyme or reason to the number system, not that Draco could see. The simulation made sure the numbers were unique, and always used four digits.

Draco glanced at the main board, and saw another grey commercial airliner had taken off. No question mark. 1205 disappeared off the board, a phantom sighting. That actually made sense, apparently Muggle warplanes often flew in pairs. Two sets of two brooms each, not three and two.

Draco started to query the middle broom, but Neville was on it. He switched his attention back to the north.

"Our brooms are intercepting theirs," Blaise said calmly.

"What do we do about those yellow ships?" Hermione asked. She didn't have any task, so she'd been watching the main board. They were moving quickly, almost as fast as brooms. They turned red almost instantly.

"We aren't responsible for ships, are we?" Daphne asked.

"Not really," said Harry. "You aren't equipped to deal with large ships, but if they are small enough you can attack them."

"Blaise," said Daphne, but he was already talking to the rest of the fleet.

Draco looked back at the board and his grey commercial plane suddenly had a red broom almost on top of it, bearing down on them.

"Incoming Red broom from the north!" Draco shouted. "Target 1745 right next to Grey 1305. Already inside yellow and why didn't it show up before, Harry?"

"They hide behind the much bigger commercial planes, in your blind spot."

The room was a rush of activity, Hermione was shifting her shield to cover 1745 while Gregory targeted it. A dogfight raged to the south, with several brooms from each side. A green broom disappeared, but then a red vanished. Then another.

"I can't target 1745," Gregory said, "I might hit the grey broom. What do I do?"

"Under no circumstances may you endanger grey brooms," Harry's voice boomed across the room. "There are hundred of innocent people on board."

"Blaise, order grey to divert and go around to the east." Daphne said.

"Shooting them down is not only morally wrong, it may drive other countries into this war." Harry was continuing in even tones, but it was distracting. Professor Asimov was saying something about the complex relationships between the Muggle governments involved.

"Can we do that?" Neville asked.

"We can try. They don't want to get shot down," said Daphne, then almost to herself, "They don't, do they Harry?"

"Besides, they are heading into a dogfight," Hermione pointed out.

"1305 is turning, I'm locking onto 1745!" Gregory shouted.

"1745 is moving back towards 1305. It's following it," Draco said.

"1305 will comply with our commands. I'm routing him in a circle, around us," said Blaise.

Draco looked at the clock, which had just shifted to 21:00.

21:30:16

Traffic had died down, there were no inbound reds.

"How does the numbering work, Harry?" Draco asked.

"The computer just gives a new number to everything. It's confusing because your computer and the other computers in the fleet see things differently at different times and use different numbers. So all those numbers that get skipped, some other crew and ship is using them. Simulated crew in this case. But if the two computers agree they are seeing the same object with two numbers they'll reconcile them."

"Speak of the devil," said Professor Asimov, and pointed to the map. A new ship had entered the eastern edge. It was green.

Despite what Harry said, apparently some parts of the communication were simulated. Blaise transferred the sound to the speaker. "Bludger, this is Skysweeper Dopplebeater Defense. We are on route to join and will be there shortly. We will receive handoff at twenty two hundred."

The red airfields lit up.

"I see six, no eight brooms from the south," Neville's voice sounded strained.

"Six from the North," Draco said.

"Dopplebeater Defense reporting eight brooms from the east. It will handle those. Informing the fleet."

Daphne inspected the map for a few long seconds, then calmly started giving orders. "Neville, watch the north east side. Blaise, tell all grey traffic to leave. This is getting ugly. I want a no fly zone one minute wider than our red line, and one minute around the Golden Snitch. Fire on anything inside that line, no warning Gregory. Hermione, swing the shields to cover as many planes as you can."

The next thirty minutes felt like hours and by ten pm Daphne's voice sounded raspy and broken. Eventually the last red broom fled the scene. They had lost three more green brooms, but no ships. The room suddenly brightened, and all of the displays except the clock disappeared. It showed 22:05:50.

"I think you did well," said Harry, "Lots to think about. We'll discuss it more later."

The rest of the conspiracy sat blinking and covering their eyes. Gregory stood up and stretched. Hermione yawned. Neville rubbed his neck, and Draco understood, he'd tensed up for the last twenty minutes.

"Are they really like that, Muggle wars?" Neville asked.

"Well, that was a particularly exciting two hours," Harry said. "Not much point simulating the days when nothing happens."

"War is six months of boredom followed by a few hours of terror," said Professor Asimov, sounding like he was quoting someone.

"And that complicated?" asked Gregory. "A general and a full staff for this?"

"The actual staff is much bigger, but I didn't want to get into too many details," said Harry. "Even in communications you might be talking to the other ships, the various planes, your own ship, superior officers to clarify orders if time allows. Compared to the real thing, this is a bare-bones simulation. Magical wars are fairly simple by comparison. Actually, that's not true. They have a different sort of complexity. But I set up this simulation because it's a good test of how you think, react, pay attention, and those questions cut across technology and magic."

"Another tough day of saving the world," Blaise said, and the rest of the Bayesian Conspiracy laughed.

Except for Harry Potter.

Author's Note - I will be taking a brief hiatus. Next chapter will be posted in roughly two weeks.