Chapter 1 — Which Bus?

That morning Iota and Wong Nam were getting ready to return a book to the library. Before they stepped out the door, Iota noticed that one corner of the book’s cover had come loose.

“Grandpa, the cover is torn.”

Wong Nam reached for a roll of clear tape. Carefully, he pressed the loose corner back down so not a single letter on the cover was hidden. Then he handed the book back to Iota.

“Can you still read it?”

Iota opened to the first page. “Yes. Thank you, Grandpa.”

She slipped the library book into her bag alongside her small notebook and a pencil.

At the bus stop, two buses pulled up side by side, so close together they looked like two siblings standing shoulder to shoulder. Iota and Wong Nam climbed aboard the bus closest to the sidewalk.

Iota took the window seat. Out her window, all she could see was the bus next to theirs, a tall green body with a row of windows full of passengers. Wong Nam sat beside her on the aisle. Across the aisle sat another window looking out onto the sidewalk, where the bus stop sign stood straight and still.

Iota pulled out her small notebook and wrote down Today we are going to the library.

All of a sudden, the windows of the green bus began to slide past. One window glided by, and then the next. Iota gripped the edge of her seat with both hands.

“Grandpa! Why is our bus rolling backward?” Iota cried out.

A mother sitting in the row ahead turned her head and smiled.

“Look at the bus stop sign,” Wong Nam said.

Iota looked across the aisle through the opposite window. The bus stop sign was still standing right there beside their bus. It had not moved forward. It had not moved backward. Meanwhile, the green bus kept rolling ahead until it cleared their window completely.

“Oh,” Iota said softly. “Our bus is standing still. The bus next to us was the one moving forward.”

Her cheeks grew warm. Moments ago she had written our bus rolled backward in her notebook. She lifted her pencil to scratch the line out as hard as she could.

Wong Nam gently rested a hand over hers.

“Leave it there. Write down what made you change your mind underneath it.”

Iota sat quiet for a moment. Then, right below the mistaken line, she wrote The windows of the other bus moved past. But the bus stop sign did not move from beside our bus. So our bus was still standing still.

“Now anyone who reads it can see what really happened,” Wong Nam said.

The doors of their own bus hissed shut, and the bus began to roll forward. Iota watched through the window across the aisle. The bus stop sign that had been standing right beside them was now falling behind, growing smaller and farther away.

“Now our bus is the one moving!”

“How can you tell?”

“A second ago we were right beside the bus stop sign. Now the sign is way back there.”

Wong Nam nodded. Iota leaned her back against the seat, though one question refused to leave her head.

“Grandpa,” Iota said. “If there were no bus stop sign, and I could not see outside at all, how would I know whether our bus was moving?”

Wong Nam smiled. “We still have a long ride ahead of us.”

“Try to find out.”