Chen Hao sat at the table, pen hovering over the paper, staring blankly at the blank surface. He had just written down the words "My first instrument, just to hear sound," when his fingers trembled slightly. The relaxed feeling from his shower was still there, but the thought of making something that could produce sound immediately made his mind heavy.

Nana stood next to him, pointing her finger directly to the center of the drawing. "The tuning peg box should be located here to secure the headstock and neck." Her voice was flat, but her words were irrefutable.

The paper on the table blew in the wind, its edges curling up. Chen Hao reached out and pressed it down, looking up at her: "You think this thing can actually make a sound? I can't even tell the difference between musical notes."

“Sound is produced by vibration,” she said. “As long as the structure meets the basic physical conditions, it will inevitably produce sound.”

"So that means... there's still a possibility he's mute?" he grinned.

“The probability is 0.37.” She paused, “lower than the probability of you slipping and falling yesterday.”

Chen Hao snorted and tucked the pen behind his ear. "Alright, let's start with the wood. Do you have a drawing? Don't make any of those twisted curves, they'll bend my saw the moment it touches them."

Nana raised her hand, and a semi-transparent projection appeared in her palm. A six-sided, box-shaped structure slowly rotated, with several sets of numbers labeled beside it. "Simplified resonator design, using straight-panel assembly, 3.2-liter volume, suitable for existing wood dimensions."

Chen Hao took a closer look and scratched his head: "Isn't this just a small box with a hole in it?"

“It’s the body of a guitar,” she said.

"Pretty much," he laughed. "Anyway, I don't expect it to play symphonies. I just need it to let me hum a couple of off-key lines."

He stood up, opened a drawer and pulled out a measuring tape and a charcoal pencil, then dragged out a piece of wood that had been left behind in the corner. This piece of wood was a lining panel salvaged from the spaceship wreckage; it was thick, with a moisture-proof coating on the surface, and felt cool and smooth to the touch.

“The length needs to be cut to sixty centimeters,” Nana suddenly said. “The error must not exceed five millimeters.”

"Come on, I'm not a precision instrument." He gestured with a tape measure and drew a line on the wooden board. "Just make sure it's close enough. If it's too much, trim it off; if it's too little, add it in. Life is that simple."

"A body that is too short will affect low-frequency resonance," she said.

“Then I’ll specialize in the high notes.” He waved his hand, “From now on I’ll focus on singing high-pitched songs.”

Nana didn't say anything more, but the optical lens flickered slightly, as if she was recording some data. She walked to the tool rack, took out a small handsaw, and gently placed it on the corner of the table.

Chen Hao stared at the saw and swallowed hard. Last time he used this thing to cut a water pipe, it took him half an hour to break it, and he almost cut his hand in. But he didn't back down. He picked up the saw and shook it. "Come on, if I don't turn this into a musical instrument part today, I'll sleep here."

He secured the plank to the vise, took a deep breath, and began sawing. The first few strokes were particularly awkward; the saw teeth got stuck in the gap and wouldn't move, so he had to stop and adjust the angle. Nana, standing beside him, suddenly reached out and gently pressed down on the back of the saw, "Maintain a 15-degree angle and advance at a steady speed."

He did as instructed, and it went much more smoothly. Sawdust fell off little by little, and a faint smell of burning filled the air.

"You understand this?" he asked as he pulled it.

"The database contains basic woodworking techniques," she said. "It includes 173 items such as mortise and tenon joints, curved surface sanding, and paint finishing."

"Why didn't you say so earlier?" he panted. "You made me overthink it all."

“You never made a request,” she answered bluntly.

Chen Hao smiled, and his grip tightened. The saw moved more and more steadily, and a straight cut slowly took shape.

About twenty minutes later, the first panel finally fell to the ground. He picked it up and examined it; the edges were rough, but the overall surface was fairly flat. He touched the cut surface with his hand; it felt a bit prickly.

"The pass rate is 82%," Nana commented after scanning.

"Higher than my test score." He put the panel on the table, wiped his sweat, and said, "What's next? Drill holes? Carve out a groove? Or should we make a neck first?"

“I suggest assembling the main frame first.” She brought up the projector and pointed to the side panel. “A sound hole needs to be made here, eight centimeters in diameter, and the position must not be offset by more than 1.5 centimeters.”

"Precision again?" He frowned.

“The position of the tone hole determines the path of sound wave reflection,” she said. “Too much deviation will make you sing like that—completely out of tune.”

Chen Hao was stunned for a moment, then burst into laughter, "You've even learned to insult people now?"

"State the facts," she said, her tone unchanged.

He smiled and shook his head, then picked up a charcoal pencil and drew a circle on another piece of wood. This time, he deliberately slowed down, looking back at the projection after each stroke. After finishing, he found a nail and a small hammer, first tapping a positioning point in the center, then slowly using a screwdriver to unscrew a circular groove.

"Does this count as manual drilling?" he asked as he turned around.

“Inefficient, but feasible,” she said. “I suggest using the rotation tool next time.”

"We'll talk about it next time." He gritted his teeth and continued spinning. "This time, we'll just make do."

The hole was finally dug. He picked it up and looked at it against the light. The opening was irregular and the edges were rough, but at least it was open. He nodded in satisfaction. "See? It's done! Although it's a bit ugly, it's the gateway to music."

Nana glanced at it and said, "The door frame is crooked by seven degrees."

“Art doesn’t follow rules.” He ignored her, gesturing with the two boards side by side. “The next step is to glue them together, right? Where’s the glue?”

“Use resin-based gum.” She walked to the locker. “Fourth compartment, brown bottle.”

He took the bottle, opened it, and smelled it; the smell was a bit pungent. He squeezed a ring of it around the seam and carefully pressed the side panel on. Then he added the top and bottom panels and secured the four corners with clamps.

"How long do you need to let it air dry?" he asked.

“It takes four hours to cure naturally,” she said. “Heating can shorten it to forty-five minutes.”

“Then heat it up.” He stood up. “I’ll go get the heat gun.”

"It's all ready." Nana took the equipment off the tool rack and handed it to him.

He took it and blew on the edge of the instrument for a few minutes. The resin dried quickly, making a slight crackling sound. He loosened the clamps to check; the four boards held up barely, wobbling a bit, but not falling apart.

“It looks like a coffin,” he said.

“It’s a resonance chamber,” she corrected.

“Yes, for the funeral of my music.” He laughed.

He sat back down in his chair, looked at the crooked wooden box on the table, and suddenly felt a little more at ease. At least it was a "thing" now, no longer just a pipe dream.

"What about the strings?" he asked. "We haven't decided what to use yet."

"I recommend using copper-core shielded wires," she said. "They meet the tensile strength requirements and are corrosion-resistant."

"Was it that bundle of black cables from yesterday?" he recalled. "I remember it being quite stiff."

“A sample has been tested.” She took out a data board. “The maximum tension can reach 70% of that of a standard guitar string.”

"not enough?"

“Pitch can be compensated by shortening the string length,” she said. “Adjusting the effective vibration length to 55 centimeters will match the standard tuning.”

Chen Hao thought for a moment, "Like if your pants are too short, you pull them up a bit?"

“The logic is similar,” she said, “but it doesn’t involve pressure on the lower back.”

He laughed again, "You're quite serious."

He stood up. "Then I'll go rummage through the scrap heap and find that section of cable."

“No need.” Nana pointed to the storage box in the corner. “It was sorted and stored during yesterday’s recycling. It’s numbered d-7.”

He went over and rummaged through it a couple of times, and sure enough, he found a neat roll of black electrical wire. Peeling off the outer sheath, he found several thin copper wires twisted together, gleaming silver.

He tugged at it, but it didn't budge. "This thing is sturdy."

"I suggest cutting it into six sections, each eighty centimeters long," she said, "to allow for adjustment."

He cut six wires with wire cutters and laid them on the table. The six metal wires lay side by side, like soldiers waiting to go into battle.

"Should we install it now?" he asked.

“The nut and tuning pegs need to be installed first,” she said. “Otherwise, they cannot be secured.”

"Here we go again," he sighed. "I thought we could just tie him up directly."

“That won’t make a sound,” she said. “It will just make a ‘pop’ sound and then cut off.”

“Fine,” he resigned himself to his fate. “Tell me what’s next, and I’ll be your construction team.”

Nana unfolded the projector again, marking the positions of the six string holes on the headstock. Chen Hao picked up the electric drill and carefully drilled the holes. His hand trembled slightly during the process, and the last hole was slightly off-center, but he didn't care and just made do.

Next, he threaded one end of the string through the hole, tied a knot to secure it, and left the other end hanging down. The six strings hung unevenly, swaying gently in the wind.

“It looks like a failed work of art,” he said.

"This is a preliminary achievement," she said.

He looked down at the piece of paper that read, "The first violin, only to hear sound," pressed it under the stone, and then picked up the saw.

“It’s time to cut the neck,” he said.

The wooden board was laid flat on the workbench, and he was about to start working.