Shay cruised up, banking her hoverboard to an elegant stop as if she'd been born on one.

"That looked a little better."

"It didn't feel any better." Tally pulled off one crash bracelet and rubbed her wrist. It was turning red, and her fingers felt weak.

The bracelet was heavy and solid in her hand. Crash bracelets had to have metal inside, because they worked on magnets, the way the boards did. Whenever Tally's feet slipped, the bracelets got all hovery and caught her fall, like some friendly giant plucking her from danger and swinging her to a halt.

By her wrists. Again.

Tally pulled the other bracelet off and rubbed.

"Don't give up. You almost made it!"

Tally's board cruised back on its own, nuzzling at her ankles like an apologetic dog. She crossed her arms and rubbed her shoulders. "I almost got snapped in two, you mean."

"Never happens. I've spilled more times than a glass of milk on a roller coaster."

"On a what?"

"Never mind. Come on, one more try."

Tally sighed. It wasn't just her wrists. Her knees ached from banking hard, whipping through turns so quickly that her body seemed to weigh a ton. Shay called that "high gravity," which happened every time a fast-moving object changed direction.

"Hoverboarding looks so fun, like being a bird. But actually doing it is hard work."

Shay shrugged. "Being a bird's probably hard work too. Flapping your wings all day, you know?"

"Maybe. Does it get any better?"

"For birds? I don't know. On a board? Definitely."

"I hope so." Tally pulled her bracelets on and stepped onto the hoverboard. It bobbed a little as it adjusted to her weight, like the bounce of a diving board.

"Check your belly sensor."

Tally touched her belly ring, where Shay had clipped the little sensor. It told the board where Tally's center of gravity was, and which way she was facing. The sensor even read her stomach muscles, which, it turned out, hoverboarders always clenched in anticipation of turns. The board was smart enough to gradually learn how her body moved. The more Tally rode, the more it would keep itself under her feet.