Rats. "'Night, Mom," she called back. She turned off her desk lamp, but took her flashlight under the covers and lay on her side. She had to use one hand to hold the light and the other to hold the notebook open flat, so she couldn't write anything down, but she was determined to get all the way to the end.
Half an hour later, her neck had a crick, and she was fighting back yawns. Uncle. She was too tired to think any more. She riffled through the remaining pages, about a dozen, then stopped and sat bolt upright, sheltering the book and the light in her lap.
Inside the back cover of the composition book, in capital letters and bright red ink, it said:
THE OATH OF THE LO-SHU CLUB.
ANY MEMBER IS MY BROTHER, AND I WILL RESCUE HIM
FROM DANGER, NO MATTER WHAT, NO MATTER WHERE.
I HEREBY SWEAR BY THE SIGN OF THE MAGIC TURTLE.
Underneath were two crosshatches and two signatures-William A. Sullivan and Robert M. Wilkins.
Bill and Bobby.
Carolyn woke up with her arms wrapped around the composition book, the flashlight down by her feet. She stashed both under her pillow and went down to breakfast, racing through corn flakes and orange juice so that she could return to her quest. Then her mother got out the vacuum cleaner.
"You can do the downstairs first," she said, as if it were some kind of treat. "I'll tackle the linens. I don't want to be ironing in the heat of the day. Holler when you've finished the living room and I'll carry the Hoover up so you can do the bedrooms-it's still a little heavy for you." She patted Carolyn on the arm.
So it wasn't until after lunch, when her mother went off to the cleaners and the bank and the drugstore, that Carolyn had a chance to get back to the notebook. She sat at the dining room table with a pile of scratch paper, going over her own sums for the third time, checking her work, when the doorbell rang.
The professor was early.
She put down her pencil and went to the screen door. An older lady with blond hair and glasses stood on the front porch in a plain blue dress, a cardigan sweater folded over one arm. Someone from the women's club, raising money for the March of Dimes again?
"Can I help you?" Carolyn asked.
"I'm Dr. Hopper. I believe I'm expected?"
Holy moley. Most of their guests were scientists. Only big brains got invited to the Institute's conferences. But none of them had ever been a lady before.
"Oh. Sure. Please come in," Carolyn said, in her most polite, talking-to-guests voice. "My mother will be home in a few minutes." She held the door open, saw a suitcase, and remembered to ask, "Do you need help with that?" Dr. Hopper was on the skinny side.
"No, thank you. I can manage." She picked up the small Samsonite case and walked into the front hall. "What a lovely home."
"Thanks." Carolyn thought hard. She'd watched her mother check guests in, but had never done it by herself. "Have a seat," she said, gesturing to the dining room table. "Would you like some iced tea?"
"I would. It's rather warm today."
Carolyn went into the kitchen and stood on a chair to get down one of the nice glasses. The lever on the ice-cube tray stuck, and the pieces came out broken, but she didn't think it would matter. She took the sweating glass and a napkin out to the table.
Dr. Hopper had a pencil in her hand, tapping it on the pile of scrap paper. She looked up when Carolyn came in. "I see you're working on the Lo-Shu problem."
Carolyn caught the glass before she dropped it all the way, but it splashed enough to soak the napkin. She set the tea onto the table. "How do you know about that?"
"I'm a mathematician." Dr. Hopper took a sip. "Legend says it was first discovered by a Chinese emperor who noticed the pattern on the shell of a divine turtle, and thought it was an omen."
"A turtle?" Lo-Shu. The light bulb finally went on. Lotion!
"That's the story." She smiled at Carolyn. "Mystical poppycock, of course. But it is the most common variation of an order-three magic square."
"Magic? It isn't math?"
"It's both." She laid the papers flat on the table. "Why don't you sit down, show me what you've found." She was a guest, but she sounded like a teacher.
"It's a square, three across, three up and down, with all the counting numbers, no repeats." Carolyn pointed to one of the diagrams.
4 9 2
3 5 7
8 1 6
"Do you see a pattern in the digits?" Dr. Hopper asked.
"I think so. The top row adds up to 15. So do the others."
"Very good. In this configuration, the sum of every row, column, and diagonal is the same 'magic' number-15."
"What can you do with it?" Sister Liguori was big on using math in real life.
"Not a thing. It has no practical application." Dr. Hopper laughed. "But that's a plus to many of my colleagues. Pure mathematics is about truth, unconnected to everyday life. They create their own perfect worlds, happily-" She turned. "Oh, hello."
"Hello. Welcome." Mrs. Sullivan stepped through the doorway from the kitchen and held out her hand. "I'm Eileen Sullivan. We spoke on the phone." She looked down at the stack of papers. "I see you've met my daughter, Carolyn."
"Oh yes. We've been discussing higher mathematics."
"Really?" Mrs. Sullivan raised an eyebrow. "I hope she hasn't been-"
"Not at all. I'm enjoying myself." Dr. Hopper stood up.
"Well, we try to make our guests feel at home here. Why don't I show you to your room?" Mrs. Sullivan headed toward the stairs. "You're at the back, on the right. A lovely view of the woods this time of year." She looked down at the suitcase. "May I take that for you?"
"No, thank you, I can manage."
Carolyn's mind kept wandering off to a place Sister Liguori had never mentioned-a perfect world where numbers could be magic. But her hands helped make dinner, set the table with the good china, and serve while her mother chatted with Dr. Hopper, who was one of the less boring guests they'd had. She'd been in the Navy during the war, a WAVE, but in a laboratory, not on a boat, working on something called a computer-a machine that could do arithmetic. Now she had a job with an important company, building an even bigger one.
"They're the first machines man has built to serve his brains, not his brawn," she said. "One day children will use something like UNIVAC for their homework, instead of memorizing multiplication tables."
Mrs. Sullivan frowned. "But then they won't learn anything."
"They will. They'll learn how to use numbers, see the patterns and connections. That's what mathematics is all about." She reached into the pocket of her sweater and took out a pack of Luckies. "Do you mind?"
"Not at all. Let me get you an ashtray." She went into the kitchen.
"What's your conference about?" Carolyn asked, leaning forward. She had never told her mother about the numbers making shapes, when they played the cash-register game, because it would sound kind of weird, but she thought Dr. Hopper probably understood.
"Let me see. Tomorrow morning's schedule has papers on combinatorics, twin primes, set theory, and imaginary numbers."
"What, like a make-believe one-fifty blibbity-blips?"
Her mother put the ashtray and a book of matches by Dr. Hopper's plate. "Carolyn! That's no way to-"
Their guest held up her hand. "It's a reasonable conjecture," she said, lighting her cigarette. "But no. Numbers like this." She took a mechanical pencil from the same pocket and drew a figure on the inside cover of the matchbook: √-1. "The square root of negative one."