"I want to learn more about changing the dreamscape."

"Awesome... is there anything in particular you'd like to learn?"

"Changing how real things are? Time?"

"Sure, outside of an imported space like this library the dreamscape is extremely malleable, it follows our expectations rather than the laws of physics. If you want something to happen hard enough it just happens unless there's someone else who doesn't want it to happen. Here inside the library and other places copied from a world the physics of that world is mostly obeyed. There is a bit more flexibility around the edges both literally and metaphorically. For example there's electricity powering the lights and climate control even though you didn't explicitly include a power station in your specification. This place needs electricity to match your understanding of it so it has electricity. It's also really easy for someone experienced with dream magic, or with the kind of prestigious talent that you have to unintentionally change things in subtle ways to go a little bit more how you want them to. What I was doing to make the world more real was to pull a little more deeply from your tether and carve out a part of the library so that only intentional dream magic can change things. It's more of a guardrail than anything. Does that make sense?"

"Yeah! It sounds fun."

"As for freezing time... you have to choose a visualization or a pattern of thought that works for you. Personally I imagine an unusually shaped bobble, a kind of time freezing from a book I read. That's why my work area is all mirrored. The dreamscape is really flexible."

"Bobble?" she asks, mostly to prompt Addy to think about it.

"Bobbles are something that people could create in a book called the Peace War by Vernor Vinge. Like I said, it let people freeze things in time." In her mind she's remembering cool tricks like freezing the top floor of a building and the surrounding hot air of a midsummer's day so that when night fell the top floor literally floated away. She's also remembering using millions of tiny bobbles to shred a tree.

"They sound neat."

"They are, they're one of my favorite fictional technologies. They have so many potential uses and implications. In one of the other stories by the author they're used to stop tornados."

She giggles. "That seems really unlikely."

"Well, it's not easy to do it but it worked after my 50th test. You need to have something to anchor the air and to bobble a large enough volume of air. It's a complicated and delicate process."

That gets a proper laugh. "It seems fun to test!"

"It was! That's the best part of the dreamscape... if I want to run an experiment I can just run it. Even if it's ludicrously resource intensive or requires different laws of physics or magic."

"I'll wanna play with that."

"Of course."

"What's a good place to start?"

"If you're going to get into serious experimentation the first thing to do is to create a safety exception for yourself." Addy pulls her own safety exception to the front of her mind. It's a list of rules for things like capping acceleration and jerk applied to any part of her body, capping the maximum electromagnetic intensity, and a bunch of other bits of minutiae. "The safety exception isn't strictly necessary but it can be pretty traumatic to feel yourself being seriously injured and that sort of thing is likely to make you wake up instinctively."

"Oh, that's smart..." she says, picking apart Addy's thoughts on it.

"Yeah... Emma had to put me back together a couple times when I hurt myself too badly." Addy carefully doesn't think about the details of those experiences.

"That doesn't sound fun."

"It wasn't..." Addy says in a low voice. Then she brightens, "But you can learn from my mistakes, and have fun safely experimenting. I think the next step in actually experimenting is learning to bookmark the state of an area. That makes iteration a lot easier."

"Okay. How do I do that?"

"The way I do it is kinda visualize a timeline and then note the current time and mark it with a flag. The specifics aren't too important you just need to indicate to the dreamscape that this state is important so it remembers it. Then you can use the same visualization or schema to tell the dreamscape to return to that state." Addy puts actions to those words and bookmarks the current time for the full library. Then she turns the table green. She waits a couple seconds and then reaches out for the bookmark and opens it which changes the table back.

She focuses, and tries to do the same thing, this time turning the table red.