“Did you hear that?” I asked. “The woman’s voice?”
Matt stared down at my high-tops. “Your shoes,” he said.
Since when was he interested in style? “I was going to wear nicer ones, but Ava said—”
“No, Jack, the voice is coming from your shoes. You got those at the lab, right?” I nodded. “They’re weight-loss sneakers. They count your steps and encourage you to move instead of sitting on your butt. There are little speakers near the ankles.”

Jack and the Geniuses in the Deep Blue Sea by Bill Nye & Gregory Mone