It's small. There's a bed with what looks like an extremely snuggly duvet. There's a small standing desk with a pad of written Hymnos which looks to be a program for how to accelerate and brake something. 

"Welcome to my humble abode." Hannah sits down onto the bed, and smiles up at Teddy. "You'd be surprised how many people you can fit in here if you work at it. But that's beside the point. You want the lowdown, right? Let me see..." she taps her chin. 

"Okay, first of all the overall structure of this place. You have el'he, rel'he, and shaldea. Guests, users and admins."

"el'he still have Heartsongs and Passion Cores, but they have a sharply limited amount of Core Draw and they can't enchant anything. They likely do not know their own Heartsong. On the whole they probably know about a dozen words of Hymnos, and use them for basic tasks like generating light or heat or keing artifacts created by others. They don't understand that what they're doing is coding on the SYSTEM, they don't know how magic works, they just have a small toolkit of common phrases and that works for them.

"rel'he have put together enough basic knowledge to amanoi. They have an understanding that Hymnos is a language that executes code. Low-level rel'he have poor singing voices, and a poor understanding of how algorithms function, but they still understand Hymnos syntax. High-level rel'he are like me, trying to build autonomous artifacts that can be operated by el'he without killing someone. Generally you establish yourself as a Muse or an Artist somewhere between the two points.

"Lastly, shaldea are elected from the community to gain control of the most secure and dangerous systems. They're able to casually call up searing flames and blinding lights, and they can throw whatever's nearby fast enough to kill. With their access, they can search you down, scry your position, and then produce one of the above nearby you, all from several miles away. There is no hiding or safety from a shaldea. Naturally, people are going to want to sound you out."

He peers at the program curiously while listening.

"Great. I'm socially some weird combination of - of - judge and executioner. All I ever wanted. Is it democratic most everywhere? What do Corruptors actually do-"

"Yeah, it's democratic most everywhere. Corruptors are people. Messed-up people, but people. They try to break the system any number of different ways. They infect people with direct contact and change their heartsongs and their minds. Blah blah. You're probably here for access to the Heartsong records so we can retrieve backups of people's heartsongs."

"...Hmm. Change them back to how they used to be?" He doesn't sound entirely happy about it.

"Better than killing them."

"Yeah, but best would be..."

Shrug.

"I don't know. This is not my place... I want to try helping with that code, to see if the skills are transferrable. What are you trying to do?"

"Build a moving platform that'll stick to a rail or something like that, move along the rail and not mow down people in the way, stop automatically instead. I'd like it to be fast but as long as it's as fast as walking it'd be useful."

"Oh, we had to do that with steam and physics. And electricity later. You can let it stick to the rail with just, like, gravity, as long as the center of gravity is low enough... Just a big boxy, uh, wagon with rows of seats, rails built into the street."

He peers at the circles again. "I think the trouble here would be as much in the physical design as the magic. I also think making it sufficiently safe and automatic is much harder than giving it a human driver and then coding safety-stop systems. Two simpler problems instead of one harder one, right? Can multiple... Enchantments, like, talk to each other?"

"Any enchantment needs to be managed by an actual person who it's pulling Core Draw from, or else draw from the Key of the Hymn with a shaldea's permission. Usually we build things to run on the Core Draw of an ordinary person, but this would take too much, it needs a rel'he to handle the forces involved, which defeats the point. So it needs to be keyed by a shaldea. That means it's part of our public image, but we can do a lot more in terms of complexity with it. Hence why I'm trying to figure out how to make it automatically guard. It's kind of possible for two enchantments to talk, but it's usually better to do it as one if you're getting something keyed anyway."

"Yeah, you'd have to be super careful with security keys like that... The way I'm used to doing code has a lot of abstractions for shared memory and permanent storage and communication between units. Hmm. Is 'person' a valid criteria for a space-search function? Do those trigger if only a small part of a person is inside them? ...Ooh, do you have electricity-storages?"

"We can generate electricity with Core Draw, but we have no way to store it. Yeah, you can search for a person."

"It might not actually be easier but I think it'd be cooler to make electricity-storages and electric motors - converting electricity to motion and vice versa. It'd be hard and complicated but it wouldn't need the Hymn at all except to charge the electricity-storages whenever they get low. Though... I don't think I understand the Key of the Hymn - does it stop needing Core Draw if you use a Key?"

"It stops needing Core Draw if you Key it, it's a permanent resource allocation on the part of the SYSTEM. The Key is a huge natural mana source at the root of the SYSTEM's physical instantiation, and it's managed by the shaldea collectively."

"...That could go wrong in several ways." He shakes his head. "I think a key would work better here than trying to make batteries and electric motors. Anyway. The problem is - keeping it from running into people. Or anything else, I presume." He looks over the code properly this time. "What do you have so far?"

"I have a good precise definition for the top velocity, a smooth acceleration and deceleration curve without too much jerk, and now I need to write up the collision detection and I need to know how far out to detect potential collisions. I think I can get the SYSTEM to calculate that for me based on the deceleration curve and the current velocity, but I haven't looked into it enough to know for sure. The controls will come last because how they're shaped depends on decisions we make here."

"I think you could do that with a bit of calculus, if the curves are also calculated? Probably you can stop a bit harder than is comfortable to prevent an accident, right? That'll might shorten the distance a bit, if there are two different stopping curves."

He looks for the parts about the the acceleration curves.

Hannah points out the symbols where they're defined. They're surprisingly complex.

He's really not used to this method of coding, but he's pretty good at math.

"I wish I had Excel and Matlab... Are there any debuggers for Hymnos? Can you register new functions?"

"You can register new programs, yes, that's essentially what we're doing here. Normally you'd enchant an item with a program and then it runs the program when you ke it, yeah? But we're using a key. You can do... subkeys? to a main program, but that takes specialized vocabulary I don't know. What's a debugger?"

"Our world's code has them, they're incredibly complicated to build, but in our world you can copy code easily so anyone can just copy one a bunch of other people made, it just can't - directly affect the world. But uh, sidetrack, a debugger executes an algorithm and displays what it's doing, but pauses at whatever steps you told it to, or will go through it one little step at a time, and reads out and displays all the values as it goes, so you watch it go and figure out why your merge sort is glitching and returning null, or whatever."

"Oh, if only."

She pauses. "- there might be one that you have access to as a data admin! We'll have to investigate that later."

"Yeah, I don't- Aww. I was in a good mood again, thinking about code." Sigh. "...I'm worried I'll pattern-match in not-useful ways, here. 'Summoned to another world with special powers to save it' is a known story archetype. I'm trying to watch myself for thinking I'm in a genre I'm not, though."

"Sounds like you need a distraction. And you do need to recharge your core, right?"

"-Ah. Um."

He is suddenly aware, again, of where exactly he is.

"...I notice that I am reflexively trying to think of reasons not to."

"Let me set aside one for you. You saw my Heartsong, yes? "When your Passion Core triggers, it triggers the Passion Cores of everyone you're touching." Think for a minute about what that implies. And about how you would optimize it. I'll wait."