There is a space at the bottom of the world, where Earth and Ice and Shadow meet. It is cold, but not cold enough to kill; dark, but not too dark to see. A small round room, made of chilly black marble, lit by a dim and sourceless glow, with a spiral stair climbing the curve of the wall and a shallow circular recession in the exact center of the floor. The recession is maybe six feet wide by six inches deep, lined with something resembling pale frosted glass, and there is nothing in it.
Manipulation of nonliving objects, more or less. Anything that could be a valid ritual target is a valid ritual component and vice versa. Flexibility of timing varies according to a number of related factors including overall ritual complexity, how many different things need to be done in close succession at that stage of the ritual, and how 'messy' the steps are - for example, a step requiring you to rotate a marked disc counterclockwise might call for very precise timing, but a step requiring you to burn a folded paper will be more flexible because the time the paper takes to burn isn't going to be identical every time.
(Part of the skill of ritual invention is in specifying which objects and actions are and are not part of the ritual: thanks to a doubly careless inventor whose name has been lost to history, there exists a ritual for enchanting permanent heat-stones that requires you to be wearing a straw hat for most of the ritual, set the brim on fire while lighting the last round of candles, and then stamp it out and knock over half the candles in the process. It makes really good heat-stones but people don't use it very often, in part because it's hard to perform the frantic hat-stomping step to within tolerances. Also because it's silly. And a fire hazard.)
—he bursts out laughing. "I'd actually forgotten about that one, it's been years since I read the book."
"What a thing to be known for. I can't decide whether it's better or worse that we've forgotten his name."
"It caught fire. And was immortalized with its brethren as an ingredient in a heatstone ritual, catching fire and being stomped on and all."
"And that's why it's important to clearly specify your ritual actions and components!"
"We have some things a little like that but it's not challenging - if I paint blood all over a workspace and then leave the bucket, I am not going to accidentally incorporate the aesthetic of a bucket -"
"Well now I'm curious if anyone's ever managed to accidentally incorporate their bucket."
"Well that's a way less humorous kind of accident than leaving the world with the legacy of your burning hat."
"My world's magic system seems - nicer - than yours. I mean, this specific iteration. The underlying cycle might also come out ahead but it's a much closer call."
"Yes, although the simple applications of mine are really quick and easy, I used to cook that way."
"—if that were my magic system I think I'd just end up feeling even more betrayed when it turned out to be secretly ending the world—"
"I mean. Yeah, that was not fun. Whoops, should not have skipped learning to fry things just because I had sheep blood on hand."
"Yeah, I can imagine. —I realize this is probably not a solution to, like, any of your top ten problems, but when things are a bit more settled I can get you cooking lessons—magic lessons, too, make your own heat-stones, if you don't mind the time investment—"
"Yeah. My instinctive reaction to any problem in my vicinity is 'how do I solve that', even if it's comparatively trivial."