He kisses her till she reacts in some way.

That is going to take a minute or two, and then

he is making out with a somewhat startled and much more enthusiastically participating Cara.

That's better.

She very much agrees!

Once she's zero'd out (having gone through a few different facial expression on the way there), she says "Well. I am bad at math."

"At math?"

"...And some other things, too, probably? But, uh. I pushed my sensory range out - really far, to the point where I could feel cars on the road, people on the far side of the sidewalk, worms everywhere in the ground beneath us, and - it's a sphere. I'm guessing from your perspective my backlash drain shot up really fast?"

She leans into him. "Thanks for stopping me so quickly."

"You're welcome. That was scary, that can kill you if you rack up enough. Does it have to be a sphere?"

She winces. "Sorry. And - good question. Okay if I test it?" 

"Yes, but stop if you get close to awakening level."

She nods, and reaches out - 

She's at the center of [the world|a 1-meter sphere]. She's stationary.

(does she have to be at the center? Can she - )

No. She's at the center of  [the world|a 1-meter sphere]. She's stationary.

(does it have to be a sphere? She pokes)

She's at the center of [the world|a 1-meter cube]. She's stationary.

(Hmmm. What about...)

She's at the center of [the world|a 0.5x1x4-meter rectangular prism]. She's stationary.

(Now she's getting somewhere...) 

She sits with her eyes closed for what is to Haru about 15 seconds. He can feel her backlash rates go up and down in response to something she's doing. It seems like she's being responsible about accumulation rates - he's keeping her close to zero.

Then the pillow next to them jumps up about a quarter of a foot in the air, and she takes a sharp intake of breath, a moderate-sized burst of backlash hitting her all at once. 

When she opens her eyes, she's grinning widely. "You're a genius! It can be any shape as long as it's symmetrical in some way and I'm at the center, and it seems pretty cheap to reposition."

"Symmetrical in some way? You could do starfish shapes? - what happens if only part of something is in your shape?"

"I'm not sure, but I think I could! I was doing a weird hybrid shape just now, a long thin cylinder for reach and longer rectangles on the ends to sweep for movement. I need to have the center of mass in my area, but as long as I do that's all that matters." 

Her grin widens. "I caught a raccoon! It was falling off a roof. It probably would have been fine anyways, but now it gets to have a softer landing and a bunch of confusion!" She giggles.

"Oh no, poor raccoon! Can you not sense things at all if they only have a little bit of themselves in your shape, or is it just that you can't do momentum stuff to them if they do?"

She closes her eyes momentarily and then opens them. "Things just aren't visible to me if I don't have their center of mass in my domain." 

"Huh! If you got very precise about adjusting the shape and finding centers of mass, you could maybe have a really thin lance of it to get better range... or, does it have to be contiguous?"

"It does have to be contiguous, yeah. I was basically doing the lance thing just now! Just with boxes on the end to make it easier to find stuff."

She tilts her head. "I do think the cost of taking momentum scales with how far I move it, though. The raccoon cost a lot more than you throwing the pillow earlier."

"How far from yourself or how far from the raccoon?"

"All the transfers have to go through me first! Raccoon-to-me was expensive, me-to-pillow was cheap." She nuzzles him.

"It could have mattered what angle the bounce was at! Doesn't seem to?"

"It does not, no. It feels like each transfer is its own separate action that I have to pay for, which makes it extra inefficient for me to act entirely at range."

"That's going to have all kinds of cool applications it's going to be hard to think of in advance."

"Yeah!! I'm really excited to play around with it and brainstorm, my -"