Chen Hao's fingers were still on the piece of wood with its clearly defined cross-section, his fingertips pressing against the densest ring of growth rings. He stared at it for several seconds, then suddenly slammed the wood onto the workbench.

"We got it all backwards."

Nana stood to the side, her optical glasses gleaming slightly: "You mean the core layer of the wood?"

“That’s right.” Chen Hao rummaged through a pile of scraps, examining each piece. “The outer layer looks sturdy, but its protective properties are actually quite weak. The truly useful parts are all inside, but we shredded them all away as scrap.” He looked up at her. “You tell me, after all that work, isn’t it like we’ve traded gold for iron nails?”

Nana didn't answer, but instead brought up the data comparison chart from before. The screen lit up, and the two sets of values ​​appeared side by side, with obvious differences.

Chen Hao clicked his tongue. "I should have tested before cutting." He squatted down, dragged out several sacks full of wood scraps from the corner, and began sorting through the core sections that had been sawed open and discarded. "Are these still usable?"

“The structural integrity is acceptable,” she said. “As long as it is not damaged by external forces, it is still suitable as a load-bearing component.”

“Then pick them up.” He stacked the five short pieces he had picked out in a row. “Four legs plus one spare, we have to use them sparingly.” After saying that, he picked up the longest piece, compared it to the height of the table, and shook his head. “It still needs to be shaped, it’s too thick now.”

He found a scraper, an old tool he'd used before when cleaning wood surfaces; the blade was dull. He tried pushing it across the wood, leaving only a shallow mark.

“This thing won’t do.” He tossed it aside and turned to rummage through drawers, looking for a more suitable tool. But after searching through three drawers, he only found a few irregularly shaped stones.

He picked up a piece and rubbed it in his palm; it was very rough. Suddenly, as if remembering something, he turned around and asked, "Do you have any information in your database about how ancient people polished wood?"

“Yes,” Nana said. “There are records of using whetstones to work wood in the late Neolithic period. Using natural sandstone of different grain sizes for grading can achieve preliminary leveling.”

“Grading?” His eyes lit up. “Then quickly give me a list, I need to find stones.”

A few minutes later, the projection appeared on the wall, showing the three types of sandstone arranged by coarseness, along with instructions on the order of use.

Following the diagram, Chen Hao went outside and collected six stones of varying sizes. He washed them clean and arranged them on the workbench: the largest on the left, the smallest on the right, leaving a transition area in the middle.

“Rough grinding, intermediate repair, and fine finishing,” he muttered, “like scrubbing a bath, layer by layer.”

The first step began. He gripped the wood with both hands and rubbed it back and forth with the coarsest stone. After just two pushes, his arms went numb from the vibration.

"This wood is really hard." He shook his hand and continued working. In less than ten minutes, his palms were hot, and sawdust seeped into the lines of his hands, causing a burning pain.

An hour later, the edges of the first table leg had finally been smoothed out a bit. He put down the stone, opened his right hand, and saw that his palm was bright red with two small blisters on the edge.

"Ouch." He gasped, gently poking the blister with his fingernail; it didn't break. After thinking for a moment, he tore off a strip of old cloth and wrapped it around his hand.

Nana walked over and said, "I suggest suspending the operation and using a robotic arm to assist in the molding process."

“No way.” He shook his head. “If this table were made by machine, it would be the same as the one I bought outside. What I’m making now isn’t furniture, it’s the first handmade product in the ‘Living Series’.”

“You didn’t care whether you did it yourself before.”

“I didn’t know this wood was so valuable before.” He grinned and added, “Besides, you only remember things when you experience pain.”

He changed his posture, holding the wood upright between his legs and using his shoulders to push the stone. Although slower, it was much more stable. Every now and then, he would stop to measure the dimensions and make marks with a pencil.

As dusk fell, the light inside the room dimmed. Nana automatically turned on the lights, and one lamp shone on his hand.

“You don’t need to stay here all the time,” he said. “Go do something else.”

"I'm optimizing the stone collection route," she said. "We can get more suitable particles from the eastern riverbank tomorrow."

"You really intend to supply me with stones long-term?" He laughed. "Alright, from now on you'll be called 'Stone-Giving Guanyin'."

She didn't reply, but simply recorded the current polishing progress and marked the manpower consumption curve.

Time passed slowly. The second core material was also placed on the workbench, but he didn't continue. The first table leg wasn't yet up to standard to secure the tabletop; there were still some bumps and dents in it.

He sat on the wooden crate, panting, and unbuttoned two buttons of his shirt. Sweat streamed down his neck, and his clothes clung to his back. Looking down at his hands, he saw that the fabric had been worn through, revealing pale skin underneath.

"This won't do," he muttered to himself. "It's too inefficient, and we're hurting people too quickly."

He got up and walked to the control terminal: "Play the data on whetstone treatment of wood again."

The scene unfolds again, starting with logging by a primitive tribe, gradually showing how ancient people used natural materials to make tools. He pauses the playback when he sees a description of "damp stone drag reduction."

"Use water?" he read aloud. "Moistening the stone can reduce friction and minimize injury to the human body."

He immediately filled a basin with clean water and soaked the three main stones in it. He took them out and tested them; they were indeed much smoother.

"That's interesting." He found a soft cloth, soaked it in water, and applied it to his palms to cool them down. After resting for ten minutes, he resumed work.

It was eleven o'clock at night, and it was quiet outside. The wind whistled softly through the cracks in the window. He drank water twice and ate half a compressed biscuit, but he didn't leave the workbench.

The third stone had become smooth, and its edges had been worn into a curve. He changed his grip, using the web of his thumb and forefinger to hold the two ends of the stone, avoiding direct pressure on the wound on his palm.

He worked on it until 1 a.m., and the first table leg finally came close to the standard size. He measured it repeatedly with a ruler to confirm that all four sides were basically symmetrical. Although it was far from smooth, at least it could stand stably.

He stood it upright on the ground and let go. The wooden leg wobbled twice, then stood still.

"It's done," he said softly, a smile spreading across his face.

But he didn't stop. He secured the second piece of material and prepared to begin rough grinding. This time, he adjusted the angle so that the light was directly facing the contact surface, making it easier to observe the flatness.

Nana whispered a reminder: "Your right middle finger is bleeding."

He looked down and, sure enough, a blister had burst, and blood mixed with wood dust had stained a corner of the stone red.

"It's nothing." He tore off another strip of cloth and re-bandaged the wound. "This little injury is nothing compared to the heartache of failing an exam back then."

He continued grinding, his movements slow but steady. He tried to maintain a consistent force with each stroke. The sound of stone rubbing against wood was exceptionally clear in the night, like some kind of metronome with a fixed rhythm.

At 2:17, he suddenly stopped.

“No, that’s not right.” He put down the stone, picked up the table leg that had just been roughly polished, and examined it closely under the light. There was a clear, deep mark on the surface, caused by uneven pressure applied earlier.

"We have to redo it," he sighed. "Half an hour of work for nothing."

He put the table legs back in the rough-working area and renumbered them. Then he sat down, massaged his shoulders, and moved his wrists.

"Why do humans have to do it themselves?" he asked Nana, looking up at her. "You could fix a leg in three minutes."

“Because you need to be sure you can do it,” she said.

He paused for a moment, then laughed: "That sounds quite plausible." He paused again and said, "Actually, I'm also afraid that one day I won't know anything and will only be able to rely on you to live. Wouldn't I then become a useless power bank? Just providing emotional value."

She didn't respond to that, but instead pulled up the stone collection route map for tomorrow and set it as the highest priority task.

Chen Hao leaned against the workbench, closing his eyes to rest. But he couldn't sleep. His mind was filled with the image of the wood's cross-section, and those unresolved details—how to improve efficiency, how to protect his hands, how to ensure that every sanding operation was worthwhile.

He suddenly opened his eyes, stood up, and walked towards the terminal.

“Let’s go over the history of tool evolution again, starting from the Bronze Age.”

The screen lit up again. He stared at it, his fingers tapping unconsciously on the table. He stopped when he saw an image of a double-handled scraper used by ancient carpenters.

"Um... could you make a simplified version?"

“Yes,” she said, “but it requires metal materials and a specific process.”

“Make a note of it first,” he said. “We’ll talk about it when we get the iron sheet.” He exited the interface, turned around, picked up the finest whetstone, and rubbed it in his palm.

Only the sounds of breathing and the occasional dripping of water filled the room. His shadow was cast on the wall, his shoulders shrugging as if he were still straining.

To the left, three unfinished table legs lay quietly. To the right, stones were arranged in a row according to their thickness. On the worktable in the middle, sawdust piled up like a small mountain, mixed with blood and sweat stains.

He grabbed the second core material and clamped it tightly again. He picked up the soaked whetstone and applied it to the surface.

The first scraping sound rang out.