Lavender and Gray.

At the next science practice, Saeon went to the experiment bench. Sodam walked beside them. Dure hugged the notebook. Teacher Gwak Doeun stood by the case.

Last math practice, Sodam had reached out first. They had begun explaining before counting every group. Saeon wondered where Sodam's hand would go today.

A long, clear plastic observation case rested on the bench. Round caps closed both ends. Two bar magnets of the same size lay inside.

“One lavender. One gray.”

Last science practice, both had been lavender. This time, only the left one was. The right bar was gray from end to end.

Saeon peered between the facing ends. The gap was as long as one magnet. The little result light in front was off.

Each magnet lay in a shallow groove on a round holder. The bars could slide a little inside their grooves. Stops at both ends kept them on the holders.

Two handles sat outside the case. The left turned the left holder. The right could turn its holder and move it closer.

Without a turn of a handle, the holders stayed facing the same way. There was no hole for a hand to enter the case. The wide hallway behind them remained open.

The teacher gestured toward the bench with an empty hand.

“Make a prediction first again.”

“We'll predict, then check.”

Saeon stood at the right handle. They wanted to see the bars stick together first. Saeon remembered the moment the two lavender bars had touched.

Sodam pointed to the handles from outside the case.

“Same two handles.”

A little white label space marked each magnet end. All four circles matched. An instruction display lit up, pointing beside them.

Saeon looked at the lavender and gray ends in the middle. This time, they looked different from the start. The handle seemed close enough to grab at once.

“Magnets always stick together.”

Sodam adjusted the arm of their glasses.

“That's still a guess.”

“They're different colors, too. I bet they'll stick.”

Last time, Saeon had said matching colors would push apart. This time felt right. Saeon raised a hand.

Sodam checked the display, then scanned the case again, leaning a little farther forward. The hand that had pointed to the handles was down.

Dure raised an empty palm to chest height.

“You already looked. That's enough for now.”

Sodam straightened. Saeon stopped above the handle, too. The magnets and handles were still at their starting positions.

Amber light wrapped around the inside of the left cap. Cloudy strands formed a round knot. Two cream-colored gaps between them looked like eyes.

Loose strands wrapped around the right cap, too. They did not touch the magnets. Both facing ends and all the white label spaces remained visible.

“Tangled at both ends?”

Through the strands on the left, Saeon saw a smooth layer. It was hard and cloudy amber. Saeon kept their hands outside the case.

The teacher opened a hand toward both caps.

“It's a device made from a mistaken idea. Tell me your reason.”

The light knots stayed inside the caps. They had no mouths, arms, or legs. They did not come toward anyone or block the hallway.

Sodam pointed to the middle from outside.

“Forget the colors. What are the facing ends called?”

Saeon read the guide beside the left end. N. Beside the right end was another N.

Different colors. Same name. Which way would they move when brought close?

Saeon pulled the raised hand back. The first gray magnets they had seen had faced N to N, too. The holders had moved closer, but the bars had pushed apart.

Sodam pointed to the two middle spots in turn.

“N and N. Same poles. I think they'll push apart.”

Saeon checked the lavender and gray bars again. This time, they first read the names Sodam was pointing to. Now it was time to watch them move.

“I'll keep the ends as they are. Just bring them closer.”

Saeon slowly pushed the right handle. The right holder moved left. The gap between the two ends narrowed.

After the holder moved about a finger's width closer, the lavender bar slid left in its groove. The gray bar slid a little to the right.

Saeon stopped the handle. A gap remained between the facing ends. The bars did not touch.

“They're pushing apart!”

Sodam kept a fingertip pointing toward the middle.

“N and N. They push apart.”

Saeon checked the empty groove in front of each facing end, too. Lavender and gray had moved in opposite directions. Different colors, but the same result as N and N before.

Then the shallow recess at the front of the base opened. Saeon let go of the handle. Dure brought their fingertips together outside the recess.

“The light reaches here.”

Inside was a little three-step stair piece. A line of light climbed its rounded edges, a little higher than last science practice.

The top slot was still empty. The rising light did not fill it with stone. There were no letters or patterns.

Saeon leaned forward slightly to see the tip of the light. At the math table, even the little stone below had glowed. Here, the line climbed below the upper slot.

All three kept their hands outside as they looked. Nobody took out or moved the piece. Saeon straightened when the recess closed.

The result light was still off. The smooth layer on the left cap remained, too. Having seen the magnets push apart, Saeon looked back at the handle.

Sodam pointed to the left magnet's end.

“Keep the colors. Change only this end.”

Saeon returned the right handle to its starting point. The original gap opened between the bars. The teacher watched the device beside them.

Dure took the left handle. Saeon let go of the right one. Dure turned only the left holder halfway around.

The lavender bar's outer end came to the middle. The gray bar did not turn. The strands around the caps stayed where they were.

Only the left end had changed to S. The right was still N. Both colors remained as before.

Sodam pointed to the starting gap from outside.

“Same gap. Same amount of push.”

Dure released the left handle. Saeon took the right. From the same starting point, Saeon slowly pushed it the same distance.

Again, the holder moved about a finger's width closer. The lavender bar slid right in its groove. The gray bar slid left.

The facing ends touched. Saeon let go of the handle. This time, the middle gap that had remained before was gone.

Sodam pointed to both ends from outside.

“Same colors. We changed the facing pole, and the result changed.”

Sodam looked at each name on the display.

“N and N pushed apart. S and N pulled together.”

Saeon checked the colors of both bars. Neither had changed. What they had changed was the end facing the middle on the left.

“Different colors don't mean they'll stick.”

Sodam drew a hand back from the middle.

“We have to read the facing poles.”

The outer strands on the left cap loosened. A crack opened in the smooth layer. The right strands pulled a little away from their cap, too.

The last strands remained. The result light stayed off. While they waited, the knots did not grow.

Sodam looked from the display back into the case and leaned forward again. Saeon opened an empty hand in front of the right handle.

Would they pull it back and bring the bars together once more? Saeon waited for Sodam's finger. The teacher said nothing, either.

Sodam stopped without being reminded and straightened. Both hands lowered below the bench.

“We saw N and N push apart. We saw S and N pull together.”

Sodam looked at the touching ends inside.

“We've seen both. This is where we finish.”

Dure looked up and opened a palm.

“Yep. Right there.”

Sodam brought a fingertip to the front of the bench and swept it once along the edge, leaving the middle result light uncovered.

The hand stopped at the end. Saeon no longer waited for it to return to a handle. Sodam had chosen this very place to finish.

The strands on the caps came undone. The smooth layer faded to cream and disappeared. The caps and bars remained inside the case.

Only then did the little result light come on. It shone at the front of the bench. The touching magnets themselves did not glow.

They had started with the same gap and moved the same distance. They had kept the colors and changed only the facing poles. They had checked how the bars moved in both cases.

Saeon looked up at the teacher.

“Not just any ends stick together.”

Saeon pictured the gap that had remained, then the touching ends. They pointed toward the middle from outside.

“Even with different colors, N and N pushed apart.”

Sodam looked at the teacher, too.

“I finished after we saw both cases. With the same gap and the same push.”

The teacher waited until the explanation ended, then nodded.

“You watched all the way through.”

Saeon took a step back. The lavender and gray magnets remained together. Nobody held a handle.

Dure closed the notebook on the shelf. Sodam turned toward the hallway without leaning forward again.

“I finished at the right time today.”

Saeon stepped alongside. At the math station, Sodam had started first. Today, even with more looking possible, Sodam had chosen where to stop.

The three followed the open hallway to the stairway door. Broad stairs and a railing continued beyond it. They were still on the lowest floor.

Saeon stayed off the stairs and looked up. The little piece's upper slot was still empty. Saeon pictured the light reaching a little higher.

What was at the top?