*No one smiled in Room 304.

Not when the bell rang. Not when quizzes were returned. Certainly not when Mr. Park wrote equations across the board with crisp, precise handwriting.

He taught mathematics like it was a language of discipline.

"There's only one correct answer," he would say, setting the chalk down. "How you arrive there matters just as much."

His classes were silent except for the scratching of pencils. He never raised his voice, yet no one dared talk over him. Every assignment was graded fairly. Every mistake was circled in neat red ink. Every compliment was earned.

To most students, he was intimidating.

One student, however, refused to be intimidated.

They challenged proofs respectfully, asked questions no one else thought to ask, and stayed after class—not to chat, but to understand why a theorem worked instead of simply memorizing it.

At first, Mr. Park found the persistence irritating.

Then... interesting.

He caught himself preparing more thorough explanations before that class, anticipating the questions that would inevitably come. Their discussions remained entirely about mathematics, but they became the highlight of his teaching week.

The realization unsettled him.

Whatever admiration had begun to grow, he knew it could never influence how he treated a student. The classroom demanded fairness above everything else.

So he became even stricter with himself.

He made sure every grade was double-checked. Every interaction stayed in the open, never behind a closed classroom door. If they stayed after class with a question, the door remained open and another teacher was usually nearby.

His students thought he had become even colder.

Only he knew the reason.

When the term ended and the student moved on, Mr. Park stood alone in the empty classroom, erasing the last equation from the board.

The chalk dust disappeared with a sweep of his hand.

Some lines, he reminded himself, existed for a reason.

He turned off the lights, closed the classroom door, and walked away without looking back.*