"Magic doesn't involve much math except when it really, really does. Long-term structural thaumaturgy is one of those times."

"How long did it take you to learn all this magic? How old are you?"

"Somewhere between the ages of 29 and 50, depending on how long I was in the Nevernever; I didn't really have a calendar, and the Nevernever has a pretty weird sense of how the length of days should work. Years 4 through 8 were mostly devoted to education in faerie culture; then, two days after my eighth birthday I accidentally turned myself weightless and jumped into the sky, at which point the focus turned to magic. And it turned hard. For the next nine years I learned about magic practically from dusk 'til dawn, which I was very pleased about. Then the death of Belinda, then enslavement for anywhere from ten to thirty years, at which point I had less free time, but my various masters generally wanted me to do magic for them, which meant a hell of a lot of magic practice and often the learning of new and exciting kinds of magic. Then I escaped and landed a job as a monster hunter, which was less varied but still a decent amount of practice. And now I'm here!"

"That's a more precise idea than I have of my own age, since the forest I started in and where both my masters also lived didn't have a night cycle - not even sometimes, like here. I might be younger than you or twice your age, I have no idea."

"Well enough. You're immortal, matters a bit less."

"A bit. I'm not nearly brand new anymore, which is usually what matters."

"Nor am I. Brand-new mortals are squishy and not good at things like punching."

"I've never even seen a new breeder fairy, let alone a new mortal."

"No great loss. People think they're cute, but they're mostly just tiny and big-headed and- hang on, I never made you a bird! That's vital, I need to make you a bird, it'll take half a minute." He plunges into another page of his sketchpad, writing out formulae with practiced ease. "I know how to do birds, I did stage magic with bird conjuration once. Made about fifty bucks, too."

"Stage magic?"

"Oh, what a curious thing," says Promise, peering at it.

"What's it supposed to sound like?" asks Promise. "Can I touch it?"

"Oh, a lot like that really, but less, uh, strangled. You can touch it if you like, I'm pretty sure you're not blocked by circles but if you are I can break it for you. It'll feel pretty much like it should, which is soft. Won't move very much, which is a pity, but that would have been a more complicated spell."

"I'm not blocked by circles. Are the mortal-faeries from Never blocked by circles?" She reaches for the bird. She pets it. She giggles.

Promise holds and pets the dove. She has no frame of reference to find its level of birdhood inadequate. "Explain the free will thing?"

"Oh man. I'm really bad at this one. Uh, so, humans and some things like humans have a thing called a soul. It's not very common for things in my universe. It's kind of like a little packet of energy that gives us the ability to make conscious decisions without being guided by our "essential nature" - like how faeries can't lie, and trolls want to eat children, and they never decided to be that way or grew into feeling it, it's just how they are and that can never, ever change. Like, you could ask a sidhe "why don't you lie?" and he'd say "because I am a faerie and that is how I am" like you're an idiot for asking, because faeries are generally assholes. Or I could say to a troll, "if you ate cows instead of human children, then I wouldn't have to kill you," and she'd say "good point, but I eat children and I don't eat cows, so I don't see how it's relevant," and then she'd probably try to eat me, because the "children" thing is more of a guideline than anything else. And then I'd kill her."

"How sure are you that I have 'free will' in this sense? How do you tell?"

"Well, you didn't run up against the circle, so I'm pretty sure now. Before that, it was just sort of a feeling I got. You get a sense for that kind of thing running around the Nevernever, it's kind of- blindingly obvious, after dealing with faeries for however long, that people with souls are different. Like, a souled woman who eats the same breakfast every morning and watches the same TV show every afternoon and swears to change the same thing about herself every New Years has more... fluidity, personality, to her, than the most unpredictable sylph. In a way. I wouldn't be as sure if the only fairies I had met were like Tacky Creep, but you personally kind of have a neon sign over your head saying "HELLO HOW ARE YOU I HAVE A SOUL"."

Promise giggles. "I think I'm unusual, though. For a fairy at all, not specifically for a leaflet or anything."

"...Now I want to perform vaguely sinister experiments on our neighbors. Look what you've wrought."

"I don't see anything that sinister about seeing if they can walk past lines on the ground."

"Nah, I just like saying "vaguely sinister experiments." Picked it up from Sally; she said it about pretty much everything my mom did, I said that it wasn't all that sinister and started saying it about everything to make fun. Then it stuck."