And then the boy’s eyes went vacant again, as if there was nobody there.

But that wasn’t entirely true either as a moment later, he stood up. All she could see was the back of him. He was balancing himself, one foot in front of the other on one of the orange vectors. He put his arms out, sort of the way you put your arms out if you’re gliding or trying to keep your balance on a skateboard or a snowboard, bent his knees down in sort of the same way you might try to glide down a snowy mountainside or the mouth or bowl at a skateboard park. Every time he put one foot in front of another, he seemed to almost slide. He looked back at her for a moment, his eyes still vacant, that slight “Colin” smile on his face, as if he was enticing her and at the same time, trying to demonstrate how she might do it, navigate her way down behind him. He was quite a bit ahead going down a straight vector that was angled toward the—she didn’t know if it was ground or what might be at the bottom of the other side of the wall. . . .

Tess ducked beneath one of the orange vertical lines, then she popped up just past it, and kept on sliding, one foot in front of the other, the way he’d shown her. That worked. She jumped over one. That worked, too, landing efficiently at a dead stop on another orange vector. But then it got complicated and Tess could see that some of the vectors of light crossed each other. Which direction was she supposed to go?

It reminded her of the tightrope at the carnival last summer and her friends, the twins, the amazing aerial ballet stars. She’d been able to handle that. Although supposedly there’d been a net below her then.

This time, there was just vast, dark emptiness below, as if she could fall into a void and never be heard of again or fall flat onto a surface, so far down it wasn’t even visible, and no one would ever know.

But “the person who used to be Max” was efficiently gliding below her and she knew that she had to follow him, figure out a course that she could take.

She swerved to the right, bravely placing her right foot on another orange vector of light, just below her, that ran like a straight line down, her toe balanced at first, and then all her weight on her right foot, and then her left foot after it. Her arms out in the air for balance as he’d shown her. Then launched into a slide.