John turned to find a frizzy-haired woman standing in a doorway.

"Looking for physics lab? You're in the right place," she said.

"Uh, thanks," John said.

The room behind was fifteen meters long and five wide. Six black-lacquered tables were arranged in two rows, and a dozen students sat around them waiting for cla.s.s. John found a seat at an empty table.

He felt someone at his elbow and turned to find the frizzy-haired woman had followed him.

"Can I sit here too?"

"I guess."

She dumped her bursting backpack on the floor next to John, then sat. She held out her hand.

"I'm Grace. Grace Shisler."

"John," he replied, shaking. "Ray-John Wilson."

"Is your middle name Ray?" Grace asked.

John blushed, embarra.s.sed to have made a mistake with his alias. "No. It's just... It's irrelevant."

"Okay, John Ray, whatever you say."

John looked around for another table to sit at, but they were all full.

"Hey! Henry! Over here!" Grace shouted. Half the cla.s.s craned their necks around, and John blushed again. He hated standing out.

Henry was a tall, gangly fellow, with dark hair and a slouch. He sat next to Grace and gave John a grunt in greeting.

"Henry's in Alcott," Grace said. "I'm in Benchley. We met at one of those mixer things they give for freshmen. Imagine that, both of us engineering majors. What dorm you in, John Ray?"

"It's just John. Um, I'm off campus," he said.

"How'd you swing that?" Grace asked. "All freshmen have to stay in the dorm. You're a freshman, aren't you? This is freshman physics lab."

"I'm a freshman, but nontraditional," John said. Without a high school diploma, without any sort of doc.u.mentation at all, he'd been forced to take the GED and apply to the UT continuing-education program. If this universe had required any ID beyond his faked birth certificate, he would have been in big trouble.

"Cool, nontraditional," Grace said. Henry grunted. "What do you think of Higgins' cla.s.s? I did everything he's covered so far in high school."

John nodded. The freshman physics cla.s.s had been utterly useless to him, but there was no way he'd be able to understand the advanced physics he needed to master the device without starting with the basics. It was why he'd decided to attend the university, to understand enough to understand the device. But everything was so maddeningly irrelevant: engineering drafting, Electronics 101, freshman physics, European history, English! Of course, what school would offer a cla.s.s on cross-dimensional travel? Maybe MIT.

"I wonder what's going to be on the quiz," Grace said. "I hope it's hard."

John glanced at her. She was smiling at him.

"You want us to sit somewhere else?" she asked.

John blushed for a third time. "No. I'm just-"

"-a little introverted?"

"A little. Not used to all this."

"Well, just sit back and relax," Grace said. "Leave the driving to me. I'm helping Henry acclimate to college too."

John glanced at Henry, who shrugged silently.

Grace was forced to, if not be silent, then at least keep her volume low as the teaching a.s.sistant explained the lab for the day. It was all about velocity, acceleration, and momentum. They dropped wooden disks down a ramp and measured the time it took for the disks to travel the length of the board at various angles. Henry worked the stopwatch, Grace recorded the times, and John dropped the disks. John was surprised to look up at the end of the cla.s.s and find they were the last ones there, having worked through the ancillary material on friction.

"That was pretty cool," Henry said, the only opinion he had uttered all day.

"Yeah!" Grace said.

"It's like a pinball machine," John said.

"A what?" Grace asked.

"Pinball," he said. "The ramp is like the play field. The disk could be the ball. If we added b.u.mpers and paddles..." He trailed off.

"What?"

"What are you talking about? Pinball?" Grace asked.

"Oh," John said. "Never mind, something I saw as a kid... in Las Vegas. Hard to explain." He realized he'd found one of the anomalies that he had been tripping on now and again since he'd arrived in Universe 7650. Like the weird soda names: Pepsi and Dutch's. He was used to Zotz and c.o.ke. And saying, "Good health!" when someone sneezed instead of, "G.o.d bless you." There was no pinball in this world.

"Oh, Vegas," Grace said. "Hey, you want to eat with us at the dining hall?"

John checked his watch. It was past five.

"Thanks, no," he said. "I have dinner at my apartment."

"Sure. Apartment food," Grace said. "I understand."

"See you next week," he said.

"Yeah, see you," Grace said.

Henry grunted.

John pried up the boards in the closet while the water for his ramen noodles boiled. He withdrew the lockbox, dialed the combination quickly, and opened it. The device was wrapped in a lambskin cloth.

It had taken him a while to stop wearing it, to put it aside. The day he had, he'd realized he was going to be staying in this universe for a long time. He took out the rest of the items in the box: a jeweler's tool set, a magnifying gla.s.s.

He realized that he needed one more thing now: a notebook. He and Henry had copied the numbers that Grace had written down during their experiment into their own notebooks. John Prime had had his own notebooks, but John hadn't bothered. He realized now that he needed to doc.u.ment everything.

He brought the magnifying gla.s.s close to the edge of the device, looking for some detail, some hint. He ran his finger across the edge. The metal was smooth and cold. There were no warm spots anywhere on the device.

John wished he had been nicer to Henry and Grace, but it scared him to befriend anyone in this universe. These people were all shades and shadows, copies of themselves, one of a billion identical people. What good was it befriending them? He was leaving one day.

The kettle whistled. He carefully packed the device and his tools away. There was a comfort in deciding to follow a meticulous scientific method in his a.n.a.lysis of the device. Sooner or later it would yield its secrets.

CHAPTER 17

"So explain this pinball thing you saw in Las Vegas."

"Why?" John said. He glanced at Grace from across the air table. They were doing a linear momentum problem in two dimensions: floating disks on an air table and bouncing them together.

"Henry wants to know," Grace said.

"Is that so?" John asked Henry.

Henry shrugged.

"He says he did a literature search on 'pinball' and couldn't find anything," Grace said.

John shook his head. "Would you launch the slug?"

Henry let the slug-the moving disk-fly. It zipped across the table toward the target disk. The camera overhead flashed four times. It whirred and dispensed a flimsy paper photograph of the disks twice before and twice after the collision. From that they would be able to calculate the linear momentum transfer between the two disks. John retrieved the target disk and replaced it with a disk twice the ma.s.s.

"Why are you checking up on me?"

Grace actually looked confused, and John realized he was being paranoid.

"We're not checking up on you! We're just-you know-interested," she said.

John sighed again. He should have changed lab partners after the first lab, but instead he'd stuck with Henry and Grace. He also should have kept his big mouth shut about things that were common in his universe and not here. Of course it was hard to know what those were until he got a blank stare in return, which meant it was better to not talk with anyone at all. But he was stuck with these two.

"It was just a game, not for betting, and there probably was only one of them ever made," John said. "And it was a long time ago, which is why you didn't find any reference."

"Explain," Henry said.

The slug hit the heavier disk and the camera flashed.

"Inclined plane, ball bearing, flippers," John said. "You bounced the ball off the scoring things until the ball slipped past you."

"I don't get it," Grace said.

"Yeah," Henry added.

John found himself explaining pinball while they bounced more disks together. They worked through six weights of disk, as well as three mystery weights, which they had to calculate via the equations of momentum.

"I'm gonna have to see it," Henry finally said, which was the most John had ever heard him say in one conversation.

"Well, we can't go to Las Vegas!" John cried, frustrated.

"We can build one," Grace said. "Henry and I are on Lab Squad."

"Lab Squad?"

"All the freshmen got a letter last year about Lab Squad," Grace said. "You must have thrown yours out. Lab Squad is the coolest student group in the engineering school. We help the senior and grad students in the lab with their work, and we get to do our own experiments during off-hours. We have keys."

"I didn't get that letter," John said.

"Oh, right, you're a nontraditional student," Grace said. "Good thing you know us. We can create a pinball project, and you can help us build a pinball... device."

"Pinball machine," John said automatically.

"I like 'pinball device' better," she said.

"It doesn't matter," John said. "We're not doing it." Anything like that, any exploitation of technology from across universes, felt too much like John Prime and his schemes for John to stomach.

"It's just a-," Grace began.

"No." John slammed the disks into their slot in the box. He shoved his notebook into his backpack and left the lab.

He wasn't going to become like Prime. There was no way John was doing something like that. Cross-dimensional trade. No way. Prime was an exploiter. He was a user, and John wasn't anything like that. And why were Henry and Grace pushing him? It was better if he just switched sessions and did lab on Mondays. He couldn't get too close to anyone in this universe. He was leaving, as soon as he figured out the device.

He found himself in the Student Union, cutting through to get to the far side of campus where his apartment was. A word on a bulletin board caught his eye: "Findlay". It was a ride share board. Someone needed a ride to Findlay, for gas. John had planned to go see Bill and Janet the next weekend anyway. He read the name on the board: "Casey Nicholson."

His hand hovered over the tab with her phone number on it. Oh, no, he thought. Not her.

He reached out and tore her phone number away.

CHAPTER 18

That Friday, John drove his car over to Benchley Hall, one of the undergrad women's dorms, but the U in front of it was jammed with cars. He parked at a student lot about a kilometer away, then walked back.