The force wavers, as if Olivia's adjusting her grip on a slippery object; it dies to nothing, returns with a shove, settles back into something approaching steadiness. The pebbles around her feet rattle.

One by one, they begin to lift off the ground. Not very far -- not more than an inch or two, as visible strain starts to etch itself along Olivia's face -- but they're entirely under her control.