"Any preferences on what it is and looks like? Or you could just shape something out of your tree, making the artefact after I've determined what I want its details to be is easy."

"I'll make myself something."

"Okay."

She goes. She comes back with a hinged bracelet-bracer-thing and another earmuff.

"So the way I'm thinking works best," he tells her after enchanting the earmuff, "is if you set down the bracelet and touch it in some specific way to activate it, and then it surrounds the flattened area with faint light so you'll know where it is."

"If the light is generally visible I can't use it to negate other sorcerers' turf advantage for long."

"Oh, you want to do that, too—wouldn't something not perfectly flat that only you knew be better for that?"

"Yes, although flat would still confuse somebody for a while."

"Okay, so—two modes, one perfectly flat for the mortal side so you can open gates, another a bit twistier and then you can study it until you know what it's like and then you can use that to confuse other sorcerers?"

"Yeah."

He scribbles something and crosses a few things out and writes some more on the piece of paper he's been writing then holds out his hand for the bracelet.

Taking it off is a bit elaborate but eventually it hinges open.

And he stares at it for a while, then—" Okay, so if you slide a thumb from here to here, it'll do the flat thing, and from here to here, it'll do the swirly thing."

"Relative to the bracelet or relative to where it is when I turn it on? How do I turn it off?"

"Where it is when you turn it on, and the bracelet shouldn't leave the area it's affecting. You turn it off by sliding your thumb in the opposite direction from the one you first used."

"What happens if it leaves anyway?"

"The effect just gets turned off."

"Okay."

"We should probably rest for today, see if we don't come up with ways this will fail horribly, and meet up again tomorrow morning."

"Okay."

He smiles and goes busy himself with something else in his world after she's gone.

She is back the next day.

"Hello. Did you think of anything to change in the plan?"

"Was it a full fledged plan?"

"Plan outline, then."