Margaret bites her lip. "Theoretically, yes, but once you know the risks you might not want it. I can't teach the thing that lets me block the side effects when something doesn't work on the first try, so if you got a line wrong in a diagram or made one mistake in the initial math or didn't specify something precisely enough in an incantation or stumbled over a word you'd get anything from a cloud of ash to a big explosion to being turned into a different species."

"Well, can you make an item that does that for me instead?"

"That sounds extremely hard to specify and might not even be possible without turning you into my world's form of shapeshifter, but on the other hand it would be world-changing if it worked. So far working on immortality and resurrection first has seemed like a better bet, but maybe multiple worlds changes the calculus in favor of metamagic."

"We have resurrection! It wants diamonds, which we understood to be finite in supply, but maybe Bar can sell us as many as we can pay for! Immortality sometimes somebody pulls it off but they don't tell everybody else how."

"Oh, wow--that changes so much. I have money but not 'huge pile of diamonds' money but if we could resurrect people that would make spell development a lot less dangerous. And maybe we could resurrect dead experts who could do the suppression thing and learn their lost knowledge! But that's got weird political risks because there was a war and enough knowledge got lost that I don't know the names of any experts who definitely wouldn't start it up again." Also she wants Bella's mom back first of everything, which risks making the politics worse, but she's going to hold out hope that she can figure out how to have it both ways.

"You need a body. And it's harder - needs a higher-circle caster, higher-circle spell - if they've been dead longer."

"Ah. I don't know where anyone is buried, but when we get out of here I might be able to find out." Also she doesn't know if Bella's mom even is buried as opposed to cremated and the best-case scenario still sounds gross. "Maybe the best thing to do here and now is for me to teach you the spells I know work, if you're okay with the risk of doing the copying wrong or mispronouncing a word. It's safer than trying to design new ones."

"I think with a ninth circle spell you can skip the body. Uh, pronouncing a word wrong in what language?"

"Any language that isn't your native language, which is going to make teaching you in here very tricky. Casting in your native language puts too much power into the spell with generally horrible consequences. No, I don't know why; if it was designed the designers did a bad job."

"I speak Osirian and Taldane. Learned Taldane as a kid though, can I still use it?"

"Did you learn it the same way learned Osirian, or in school? But I should be standing by the first time you cast something anyway."

"I learned Osirian at home and Taldane by stealing my brother's homework and talking to neighbor kids."

"You'll probably be fine, then. So the first thing to go over is runes and their meanings, I think. Bar, can I borrow a copy of--" she names the rune dictionary she learned from and wishes she could even get to just the garage she was came in here from.

Bar produces a copy.

Explanations time! Here are the possible meanings runes can have; each rune has a bunch of meanings in different ratios, scaled by the size of the rune. You want your diagram to contain a bunch of the meanings you want and as little as possible of the ones you don't. By arranging them like so you can get the second set to cancel out the side effects of the first set, then the third set to cancel out the side effects of the second set, and so on. She uses the spent water-boiling diagram as an example because it's fairly small.

"Well, that's nastily mathematical - you don't have to go adventuring to make the big diagrams work, or anything, though?"

"Nope. If you get the runes and the incantation right, it works. And if it's a fresh diagram; it gets used up even if you make a mistake and then you have to draw it again."

"Huh! You could teach people to copy diagrams in - days - and to use them in hours - this'll be amazing."

"It's still extremely dangerous. It sounds like you have people who are used to dangerous magic and ways to mitigate the risk, but it's important that everyone know what they're getting into."

"They can make enough to cover the insurance, I reckon. But do give me all the safety warnings, I don't want to make the actuaries annoyed with me."

"Don't cast in your native language. Double-check your meaning math and if possible have someone else double-check it. Use a straightedge and a protractor to draw your runes and then double-check that. Incantations should leave as little ambiguity as possible. Cast in a quiet place with no interruptions so you're less likely to trip over a word . . . I should get you a book on it, I want to make sure I don't miss anything and a book will have examples of the consequences of mistakes so you can get set up to mitigate them." She returns the books she doesn't need anymore to Bar and gets the book of runecasting accident case studies she has such unnerving memories of.

"What does count as a native language, some people are brought up speaking Osirian and Taldane both at home," Ismat says, jotting down notes.

"They'll need to cast in a third one, then; it has to be one you learn formally instead of picking it up as a baby. Also, I need to emphasize: all of those rules are for casting something that's already been tested. I don't know how to develop new spells safely. I still have to do a bunch of trial and error most times that would probably kill anyone else. I should test the translations of the spells I know into a couple different languages on your world; translating can introduce meaning changes."

"That happens with people developing wizard spells too, sometimes they explode. How're you going to translate them?"

"Well, the translation effect in here has been good enough not to trip us up in ordinary conversation, so it's at least a first pass. If I say the incantation out loud and then you write it down in Taldane then it'll be in Taldane and I can look at it written down and see if translating it back has introduced any changes."