The little program could not tell a three from an eight, and Maya was starting to take it personally.
They had drawn the digits themselves, two hundred of them, on index cards, then photographed each one with the cracked phone clipped to a lamp. Soren had written a training script from a tutorial. Now the laptop fan whirred like a trapped bee, and the screen said the model was correct sixty-one percent of the time.
"Sixty-one," Maya said. "A coin gets fifty. We are barely beating a coin."
"More cards," Soren said. He did not look up. "The tutorial said more examples."
So they drew more. Another hundred. The fan whirred again. Sixty-eight percent.
Maya leaned back and stared at the two numbers. Two hundred cards, sixty-one. Three hundred cards, sixty-eight. Something about the gap bothered her, the way a crooked picture frame bothers you from across a room.
"It went up seven," she said. "For a hundred more."
"Good," Soren said.
"No. Listen. The first two hundred bought us eleven points over the coin. The next hundred only bought seven." She tapped the table. "It's slowing down. But not randomly. It's slowing down on purpose."
Soren finally looked up. That was the kind of thing he could not leave alone, a slowing down that felt deliberate.
"Draw two hundred more," he said. "I want a third dot."
They drew until their hands cramped. Five hundred cards total. The fan worked harder this time, longer, and the number that came back was seventy-three.
Soren wrote the three results on the back of an index card. Two hundred, sixty-one. Three hundred, sixty-eight. Five hundred, seventy-three.
"Each time we add cards, the jump gets smaller," he said slowly. "But the smaller it gets, the more predictable it looks."
Maya grabbed the card. "What if it's a curve we can draw before we get there?"
"You can't know the future of a thing you haven't run."
"Why not? The numbers already know it. Look at them." She held the card up like evidence. "They're sitting on a line."
Soren did the thing he did when he wanted to be sure. He pulled the calculator app and treated each gap as a ratio instead of a difference. Doubling the cards from two-fifty to five hundred had closed the gap to a perfect score by a steady fraction. Not a random amount. The same fraction each time you doubled.
"If that holds," he said, and his voice went careful, "I can tell you what a thousand cards will give us. Before we draw a single one."
"Do it."
He did the arithmetic twice because the first time felt too clean. Then he wrote a number on the card and put his thumb over it so she couldn't see.
"Now we draw," he said.
Maya groaned, but she was already reaching for the marker. They drew for an hour. They drew threes and eights until the shapes stopped looking like numbers and started looking like knots and snowmen. They photographed every one. A thousand cards. The librarian upstairs flicked the lights once to mean closing soon, and they pretended not to see.
Soren ran the training. The fan screamed. The bar crawled. Maya watched it crawl and did not breathe much.
The screen settled. Seventy-eight percent.
Soren lifted his thumb off the index card.
Written there, in his small careful handwriting, from an hour before they had drawn a single new card: seventy-eight.
Maya stared at the card, then at the screen, then at the card.
"You knew," she said. "You knew before it existed."
"The curve knew. I just read it."
That was the part that opened under Maya like a trapdoor. "So if we wanted ninety," she said slowly, "we wouldn't guess. We'd read off how many cards. Off the line."
"Thousands," Soren said. He squinted at his own arithmetic. "A lot of thousands. The line keeps going up, but it makes you pay more for each point near the top."
"It never lies, though." Maya pulled the laptop toward her. "It just tells you the price."
They sat with that. Outside the high basement window, feet went by on the sidewalk, ankle-high, ordinary.
"This is the thing nobody told me," Maya said. "I thought the smart programs, the giant ones, somebody got lucky. Somebody had a flash." She shook her head. "Nobody got lucky. Somebody drew our card with bigger numbers and read off how much it would cost to get there. And then they paid it."
Soren was already writing, the pencil moving fast. He sketched the three dots, then the dotted line continuing off the edge of the card, off the table, he half-stood to keep the line going as if it could leave the room.
"It doesn't stop," he said. "That's the strange part. We have three dots from a library basement. The biggest models anyone has built are just more dots. On the same kind of line."
"So the line goes through them and through us," Maya said. "Same line."
"As far as anyone has checked, yeah. It keeps holding. Nobody's totally sure why it holds." He set the pencil down. "That's the part that gets me. It works and works and nobody can fully say why it should."
Maya looked at the card with seventy-eight written on it, written before the truth had happened, correct anyway.
"You felt out of place your whole life," she said, not really to him. "For wanting the line under the magic."
"Yeah."
"The line was real the whole time. You were right to look for it."
The librarian flicked the lights again, twice now, meaning it. Soren tore the index card free from the stack, the one with three dots and a line running off its edge, and slid it into the back of his notebook where it stuck out past the pages.
Maya pressed the trackpad and queued the model to train again, on every card they had, while they packed. The fan spun up in the dark, climbing the same slope, paying the same price, on its way to a number Soren had already written down.
Read the interactive version, listen to the narration, and earn a gold star →
A science-verified short story for curious kids · Curiosity Land