[ He really, really was like a stray cat. Skittish and shy, but maybe . . . with the parts in front of her offered up like tuna and toys, with her hands and self still centred where she sat (and that was important, that he could choose how close he came or how far away he sat, that he didn't feel scared or trapped) . . . maybe, like this, they could talk for a bit.

Her screwdriver turns the ring of the rotor on its side, tilting it so he can see the groove running around inner edge. ]

The divide here, under the auxiliary coil—that's the conduit for the power recovery system. Other parts connect to the driver unit and the battery, but here . . . this is where it starts. This is where everything begins.

[ She slips the two pieces back together, and takes what has to be the main bolt from her lap and runs that through the centre. It's the absolute barest of wheels, but she holds each side of the bolt between thumb and forefinger and runs the 'rim' firmly over the ground anyway. ]

The batteries that run the system . . . they're the same size as the ones in cellphones. Even supercharged, they can't run all the components for long.

[ As she lifts the 'wheel', momentum seems to keep it spinning . . .

. . . and spinning . . .

. . . and no, it's the motor, completely disconnected from any power source and still running. ]

Any transfer of energy incurs a loss. You can't stop entropy. But if you can minimize that loss—if you can transfer kinetic energy to kinetic energy with only losing 1% of that output, if you can recharge just by using the weight of your body and gravity—

[ The motor finally begins to slow, and she looks up at him, offering the best thing she possibly can. ]

Then you can fly.

[ Catnip. ]