7

It wasn’t until she was on the sidewalk and headed home that Kendra realized she had no idea what to wear or how to behave when she arrived at Carlisle’s Pub that evening.  She mentally reviewed her wardrobe: one bathrobe, sensible clothes that wouldn’t alarm her professors, a business suit for meeting money people, running shorts that she hadn’t worn for a year, and sweats and a T-shirt both flecked with the tiny holes that were signs of age in knitwear for the few waking hours she spent in her apartment.

“Ohmigod,” she whispered.  “I have nothing to wear.”  She hadn’t had occasion to feel that way since she’d been fourteen--come to think of it, perhaps LB…Elle could help.  It was time to start tutoring the kid anyway.  Kendra sighed.  She’d have to be careful not to let Elle know that she needed advice or the girl’s head would swell too much to stuff any physics into it.

Kendra changed course, and instead of heading to her apartment, she walked back to her lab.  She sat at her computer and pulled up her equation.  She calculated a travel arc that should  land her in Elle’s room a few minutes after the girl’s curfew, but the pressures of the final months of the PhD program must have taken more out of her than she’d thought.  She landed face down on top of Elle, who’d been asleep. 

“Ow!” cried the girl.

“Shhh!”  Kendra clamped her hand over the girl’s mouth.  “It’s me.”

The Little Bitch bit down.

“Ouch!”  Kendra drew her hand away, giving LB the diversion she needed to dump her older self on the floor. 

“God damn it!” Kendra whispered loudly.  “I told you I’d be back to tutor you.  Why are you being such a jerk?”

LB sprang out of bed, and snapped on her desk lamp.  The girl wore a black tank top and yellow Lion King pajama bottoms.  Kendra glanced at her own ensemble:  pleated tan khaki pants, brown flats, and a light blue short-sleeved blouse.  Even in pajamas, LB…Elle looked more cool than she did.  Kendra hid a smile.

“What are you grinning at?  You are a lezzy, aren’t you?”

“No, and even if I were, lesbians are cool now, so what are you worried about?”

Elle wrinkled her nose.   “Yeah okay, but…licking…down there?”

“You have the same anatomy.  How can you be such a misogynist?”  Kendra stared at her younger self, perplexed.  It was the wrong thing to say.  The girl stared back at her with defiance. 

“Never mind,” Kendra said and backed away from the toxic murk that was teen sexuality.  “I’m sorry I landed on you.  Let’s get busy.”

“Just like that?  Where were you when I needed you for math homework all week?”

“Working on my landings and fending off industrial spies.”

“Really?”  The girl’s mask of bored superiority slipped for an instant, but only for one.  “Well, I hope you’re better with spies than you are with time travel.”

“Let me see your math and science texts.”

Elle sifted two books out of the stack on her desk and plunked them down in the circle of light on her desk.

“How are your grades?”

Elle clicked her tongue against her teeth, crossed her arms, and stared sullenly at the floor.

“That good, eh?”  Kendra opened the algebra text.  “Show me where you are.” 

While Elle looked for the appropriate section, Kendra sifted through the girl’s spiral-bound notebooks until she found the one with math notes and assignments.  The kid had tried the last few days, but had no sense of the power of math.

Elle nudged Kendra’s arm with the algebra book.  “We’re here.”  She pointed to a section on trinomial equations. 

Kendra took the text, and flipped back toward the beginning until she found the chapter she was looking for.  “The heart of what algebra has to offer on its own is here in chapter three--”

“What do you mean, ‘on its own’?”

“Algebra and geometry don’t really fly until you get into calculus.  They’re precursors, and not a lot of fun on their own.”

“So why do they teach us this stuff without calculus?”

“I don’t know.”  Kendra studied her younger self for a moment.  “Want to see if it makes more sense to you with some calculus?”

“Okay.”  Elle shrugged. 

“We need to find a problem to solve.”

“What do you mean?  There are tons of problems in the book.”  Elle sounded worried.

“Yeah, but most are designed to avoid calculus.  Let’s check science--biology, hmm.”  Kendra flipped rapidly through the text.  “Okay, take capillary action for example.”

“We covered trees at the beginning of the term.”

“Good, then you’ll appreciate this. Remember that the height of the column can be figured using this equation.”  Kendra wrote the equation from memory as she spoke it aloud.

“Um, I don’t think we learned that.  We don’t take geometry until next year, so I don’t know what a cosign is.”

“That’s the beauty of calculus.”  Kendra launched into an explanation of the dynamic real-world number-crunching power of calculus compared to static algebra and geometry.  Elle’s eyes glazed over.

“Sorry,” said Kendra, noticing Elle’s shoulders, slumped in defeat.  “I’m doing this backwards, like your teachers.  Tell me about some of the problems in your life, and we’ll solve one with math.”

Elle launched into a dizzying account of her complicated social life.  Kendra thought her brain might explode.

“…and I have to wait until the stupid things go on sale, because Mom and Dad give me such a tiny allowance,” her younger self complained. 

“Ah,” Kendra’s numb brain seized on what seemed a concrete problem.  “Would it help you to know when things were likely to go on sale?”

“Yeah,” Elle annunciated two tones of sarcasm, as if Kendra were dense.

“Okay.”  Kendra showed LB…Elle how to find market trends and how to plot a price curve.  “You can get as complicated as you want to, but probably watching the major producers in Asia, and the major consumers in the West will get you a prediction accurate to within a week.  There will be a lag in the price variable between New York and Kansas, of course, but once you figure out what that is, it should stay fairly consistent.”  Kendra looked up.

“Well, duh,” said Elle. 

Kendra took that as a sign that she understood, and decided not to be insulted.

“The real power comes from understanding the long-run marginal cost curve.  The manufacturers want to make a profit.”

“So?”

“So if we use an integral equation to find total cost over a period, and plot that against the differential of consumer price, then--”

“Hold on.  Won’t that make a three dimensional curve?”

“Yeah, and we’ll find the peaks that correlate with your favorite stores in Wichita.”

“Cool!”

Just after midnight, Elle figured out when the fall wardrobe she wanted would go on sale.  “But that’s too late!” she wailed.  “That doesn’t help me at all.”

“Okay, what do you need to know that would help?”

“I guess if I knew when things would be on sale farther ahead, like a year, that would help.”

That ought to earn me a couple of favors, Kendra thought. 

By dawn they had used indefinite integrals to find the functions that described the fashions for the next ten years.  They plugged in their unique variables, and spit out some real results.

“So are these right?”  Elle asked.  “You’re what, ten years older than I am?  You ought to know.”

“I’m five years older than you are,” Kendra half-snarled. 

“Geesh, you must be really hard on my body,” Elle objected.  “You look older.”

“Hey, it’s my body, twerp.”

“What are you so mad about?  All I said was that you should know if these fashions are right for the first five years…but you don’t, do you?” Elle asked, notes of disbelief and wonder in her voice.

“No, I don’t.  I eat and sleep irregularly, and I work.  Now it looks like I’ll be tutoring you, so when would I have time to read a fashion magazine or shop?”

“God, chill a little, would you?”  Elle squinted at her.  “This might be the weirdest sleepover I’ve ever had, but you know, you would look pretty hot with a little makeup.”  Without further ado, she made up Kendra’s face, then smiled.  She turned Kendra toward the mirror over her bureau.  “What do you think?”

Kendra looked at herself, expecting to see some outrageous parody of adult style, but she liked what she saw.  Her lips looked full and sexy, the circles were gone under her eyes, and she actually had a healthy glow.  Her eyes were best.  She looked almost as powerful and mysterious as Xenopoulos.

“Wow.  Pretty good, kid,” Kendra whispered.

“At least you haven’t gotten fat or anything,” Elle said with uncharacteristic cheer.  “I think I have some clothes you could wear.”

“What, and look retro or something?” Kendra objected, and then wondered why she would care.

“Hey, our equations showed predictable recurrences and even persistence of a few trends.  You’ll be fine in a tank and jeans.”

Kendra wanted to ask if Elle had another black tank, but instead she said, “It’ll be cold when the sun goes down.  It’s February in California, about 40 or 50 at night.”

“Black leather jacket,” the girl said without thought.  “Do you still have this one?”  LB hoisted a new version of a jacket that Kendra thought might be moldering in the front closet of her apartment.  “Um, I think so.”

“Can you take this one just in case, or would that fuck up the time-space continuum?”

Kendra laughed.  “We can assume that’s a myth.  You and I are mass of the same origin, currently occupying the same moment in time.  Essentially we’ve doubled, but neither of us has exploded or gone crazy.”

“Assume?!  You mean you didn’t check that out before you started hopping back here to bug me?”  Elle asked, truly angry.  She shoved her jacket back into the closet.

“Kendra?” called a voice from the hall.  “Are you all right?”  It was Kendra’s mother.

Both Kendras opened their mouths to answer, but the older version caught herself in time. 

“Yes, Mom.  I’m fine.  I was talking to myself.”

“Okay.”  Their mother didn’t sound convinced, but Kendra heard her go into the bathroom.

“I better get going.  Study hard.”  She touched the reversal button on the remote in her pocket.

“Wait!” Elle shouted.  “You didn’t answer my--”

“Question,” Kendra finished her young counterpart’s complaint, as she stepped into her lab.  “Well, that was better,” she muttered, referring to her landing, but thinking about her time with Elle.  She glanced at the time, almost 9 p.m. already, but she’d have time if she hurried.