And Lúthien's there, wearing pants and with significantly shorter hair. She claps her hands delightedly. I can see you!

Loki hadn't considered what she'd be wearing in the mind palace; she looks down at herself, and of course there's her usual armor-as-daywear. She looks back up and grins in reply.

So usually it's played as, like, an elaborate and destructive game of hide-and-seek. When the other person does something to the house, you can oppose it - say to yourself 'no, wait, that didn't happen' and that'll usually undo it, but that's less fun, it's the most fun if you just try to top it. Do you want me to start? Running away involves more creating on the fly, chasing someone involves more crashing everything everywhere."

One question first. Is flying cheating?

I've never heard that before. ...Don't think so.

Marvelous. Catch me if you can. And Loki's zooming down a hall, bearing left into a four-story greenhouse and zipping into a maze of trees.

A plate falls out of the greenhouse ceiling and water comes rushing in from the sky.

Loki dives into the resulting puddle, turning it into a series of underwater caves populated with distracting fish, and slips into a coral reef.

A shark appears in mid-caverns, scattering the fish, and then an octopus who makes everything go dark in a puff of ink that probably dramatically exceeds the capabilities of real octopuses.

The dark water is empty space, filled with glittering stars, high over a ringed planet; and Loki has a spaceship. This is a little unfair, but she thinks Lúthien will be more intrigued than anything. Zoom, to that nice-looking moon over there.

The osanwë-reaction is indeed enchantment and delight. A pause, then - a giant hand reaches down to close around the moon and throw it across space for a dog to catch.

Oh, are they wreaking that much merry hell with scale? Loki zips into the dog's fur and races between hairs until they give way to grassland, each blade ten feet high and the wind whipping it all around.

A dense thicket of thorns.

A burrow under them, full of voles and fluorescent mushrooms.

The earth starts shaking.

The next corner Loki turns leads to a storm-tossed ship, and she climbs to the deck and turns into a bird (carefully; she doesn't want to actually trigger the spell) and zooms towards a tropical island.

The island explodes into sparkles as she gets near. I give up, Lúthien thinks, You win. That was astonishing. Most people stay in the house. What was the dark space with the floating globes?

Space. That's where most people live, is on giant spherical rocks turning among the stars in space. Your world is odd; most suns are older than their planets and I'm not sure what your stars actually are; but our stars are incredibly distant suns.

She tries to call the image back up. How would you live on something moving?

Have you ever been on a boat? Or - a horse, maybe, a fast one.

The response is just an image of her father's scowling face.

Okay, well... if you go on something that is moving, you'll feel wind; but after you've settled at a speed, you won't go sliding off the back of the thing. The only time that will happen is if the speed changes, and it can happen either way. Osanwë: even better for visual aids than illusions in some ways. If it speeds up, you'll have to hold on or you'll fall off the back; but if it suddenly slows down or stops, you'll have to hold on or you'll fall off the front. As long as it stays a single speed, you just go along with it. Standing on a planet is like that. They turn and turn and turn, and zoom through the void in ellipses, and they do it very fast - but they don't change how they're doing it suddenly.

Huh. When you have teleportation, will you be able to go there?

To planets? Yes, if I want to be able to go anywhere I've heard of that isn't in this realm, like home.