Chen Hao leaned against the sheep pen fence, his hands empty; the cup had been placed back on the counter. He yawned, his eyelids feeling heavy.

He felt so comfortable drinking that warm milk; it made him feel completely relaxed. He squinted, listening to the rhythmic sounds of the extruder, one beat after another, like some kind of heavy metronome.

Nana stood in the center of the platform, the robotic arm slightly adjusted its angle, and the optical lens scanned the equipment area. "The main system is running stably, and the drip irrigation flow rate meets the standard."

“Our little workshop is now considered a legitimate business.” Chen Hao grinned, then sat down on a small stool next to him, with half a discarded steel pipe lying at his feet.

He had barely closed his eyes when the voice in his ear changed.

The previously steady compression sound began to be mixed with a low hum, like someone banging on a tin bucket with a stick, muffled and annoying. He frowned, but didn't open his eyes, assuming it was normal vibration from the machine just starting up.

But the sound grew louder and louder, and the rhythm remained unchanged, continuing uninterrupted.

He opened his eyes and looked up at Nana: "Did you hear that? What's that noise?"

Nana's optical glasses flashed: "Audio detection shows that the noise level in the main device area has reached 87 decibels, exceeding the safety threshold."

"What do you mean? Are you making noise?"

"Long-term exposure may affect the nervous system, and there is also a risk of ecological disturbance."

"Could you be a little more direct with your words?"

"The birds have arrived."

Chen Hao turned his head to look outside the protective netting.

Before nightfall, a group of dark shadows hovered in the distant treetops, wings outstretched, circling back and forth, neither moving nor landing. Several crashed into the protective netting, bounced off with a snap, and flew back to continue circling.

"Are they crazy?" He stood up, rubbing his eyes. "Don't they usually avoid us?"

"Monitoring data shows that the flight frequency of the flock of birds is highly synchronized with the vibration frequency of the hydraulic pump." Nana pulled up the waveform diagram. "Inference: Mechanical resonance triggers a biological stress response."

"So... this machine is so noisy it's made the birds stupid?"

"The probability of the conclusion being true is 89%."

Chen Hao scratched his head: "Then what should we do? Turn it off?"

"Shutting down the irrigation system will lead to irrigation disruptions and increase the risk of crop water shortages."

"We can't stop," he sighed. "Then I'll have to take over."

He grabbed a wooden stick leaning against the wall and strode towards the fence. Halfway there, he turned back and shouted, "If you dare say I'm showing off, I'll turn your loudspeaker into square dancing mode!"

Nana did not respond.

More and more birds gathered outside, and a dozen or so began swooping down and crashing into the protective netting. The metal mesh rattled from the impact, and several connection points creaked.

Chen Hao ran around outside the fence waving a wooden stick, yelling, "Get out! All of you get out! If anyone bumps into it again, I'll tear down its nest!"

A large bird suddenly swooped down from the side, its wings whipping up the wind, and its claws reached straight for his arm.

He was a fraction of a second too slow to dodge, and his left arm felt cold and then burned with pain.

Looking down, I saw three scratches with beads of blood seeping out.

"Holy crap!" He jumped back two steps. "They even used a sneak attack?"

Nana immediately approached, and the robotic arm deployed its medical module: "External skin laceration, requires cleaning and bandaging."

"Don't worry about me!" he swung his arms. "The net's about to give way! If we keep crashing like this, we'll be sleeping outdoors with the sheep tomorrow!"

Nana turned to the equipment area, where optical mirrors flashed rapidly as data streams were quickly compared internally. "Knowledge base retrieval complete, acoustic model matching successful."

What did you say?

"The main frequency of the noise is 62 Hz, which is within the range that birds are sensitive to. It is recommended to adjust the hydraulic pump's operating frequency to 45 times per minute to avoid the resonant frequency band."

"Doesn't that mean it's slower? The efficiency drops by half, right?"

"Output can be maintained by manually compensating for pressure."

"I have to step on it myself?"

"yes."

Chen Hao gritted his teeth: "Fine, I'll risk it."

He limped back to the control panel, took off his coat, and used it to bandage his wound, pressing down on the blood. "You keep an eye on things outside, I'll adjust the machine."

The foot pedal lever is connected to the spring energy storage device. He bent down to check the connecting shaft and found that the fixing screw was a little loose. After tightening it, he tried stepping on it twice. The piston moved smoothly, but each time it was fully compressed, it made a sharp metallic friction sound.

"This lousy voice needs to be changed," he muttered.

After scanning, Nana indicated: "Insufficient lubrication, it is recommended to add vegetable oil."

"Where did the vegetable oil come from?"

"The milk fat byproduct separated from the last milking can be processed and used as a temporary lubricant."

"You even calculated this?"

"Maximizing resource utilization is the basic logic."

Chen Hao pulled out a sealed jar, poured out some pale yellow grease, and smeared it into the bearing gaps. He stepped on it again, and the sound was indeed much quieter.

He stepped on the valve ten times in a row, and the pressure was full. The solenoid valve clicked open, and the water flowed back into the main pipeline.

At the same time, the buzzing sound from the outside world noticeably decreased.

The flock of birds' flight rhythm has become disordered.

The once orderly circling became scattered, and several birds began to descend and tentatively fly away.

"It worked!" Chen Hao gasped for breath. "It seems the commotion really was the culprit."

Nana added, "Simply reducing the frequency is not enough to completely solve the problem. I suggest planting sound-absorbing plant strips around the perimeter, using the density of the leaves to absorb sound waves."

"Plant a tree? It will take several months for it to grow."

"Choose fast-growing vines; they can cover the outside of the protective netting in three days."

Where did the seedlings come from?

"The spare nutrient tank contains a variety of pothos, which has a short growth cycle and a well-developed root system, making it suitable for transplanting."

"Then you go dig, and I'll carry it."

The two split up. Nana used a robotic arm to cut the connecting pipes, removed three empty resin tanks, and moved them to the outside. Chen Hao, enduring the pain in his arm, dragged over some old supports and fixed them to the outside of the protective netting to form a vertical planting frame.

The vine seedlings were taken out of the nutrient solution, their roots wrapped in damp cotton cloth, and then inserted one by one into the support frame.

"Does this thing really block out sound?" Chen Hao asked while planting seedlings.

“Sound has been replaced with ‘noise’,” Nana corrected. “Experimental data shows that thick-leaved plants can reduce sound energy transmission by more than 30%.”

"Can't you speak like a human being?"

"able."

Chen Hao rolled his eyes: "Then why didn't you say so?"

"Because your question was not phrased precisely."

"I..." He opened his mouth, but finally managed to say, "Never mind, forget I asked."

They connected the drip irrigation branch to supply water to the newly planted vines. The water flowed down the thin pipe to the roots, and the leaves trembled gently.

As night deepened, the noise level in the equipment area dropped below 70 decibels, and the extruder was running smoothly, albeit at a slower pace.

Chen Hao sat at the control panel, his left hand wrapped in simple gauze, his right hand resting on his knee, staring at the outside of the protective net.

The flock of birds had mostly dispersed, with only a few remaining watching from a distant tree, no longer approaching.

"Is everything alright now?" he asked.

“The acoustic environment is stabilizing,” Nana replied. “It is expected that the vegetation strip will form a preliminary sound barrier in 72 hours.”

"Then I can finally get a good night's sleep."

As he was speaking, he suddenly heard a soft sound.

It wasn't a machine, nor was it a bird's call.

The spring pin of the foot pedal lever was stuck, and the piston failed to fully return to its original position.

He frowned and stood up: "Is something wrong again?"

Nana's scanning interface: "Metal fatigue caused deformation, parts need to be replaced."

"Change what? Where's the spare part?"

"spare part" is the Chinese equivalent of "备用部分" (spare parts).

"I know! I'm asking if it exists!"

No stock available.

Chen Hao stared at the swaying lever and sighed, "So what do we do now? Crank it by hand?"

"Temporary reinforcement can be tried."

"Where are the tools?"

Nana handed over a wrench and a piece of metal.

Chen Hao took it, squatted down, inserted the metal strip into the connection, and tightened the bolt with a wrench. He used too much force, which pulled at the wound on his left arm, causing him to gasp in pain.

"Be careful," Nana said.

"What did you say?" He looked up. "Were you just concerned about me?"

"I'm just trying to avoid causing the system to crash due to operational errors."

“Oh,” he grinned, “that means you didn’t care.”

He continued tightening the screw, and when it stopped at the last turn, he gave it a sharp tug—

Click.

The bolt broke.

The metal strip was bent, and the lever was completely jammed.

The extruder has stopped operating.

The drip irrigation system subsequently stopped working.

Chen Hao froze, watching the broken bolt roll to the ground and slowly come to a stop.