When the waterwheel slowed down for a moment, Chen Hao immediately squatted down in front of the terminal, swiped his fingers across the screen a couple of times, and frowned so deeply he could have trapped a mosquito.

"Didn't we just say the closed loop was established? Why is there another problem?"

Nana stood beside him, her gaze sweeping over the data stream: "The water flow direction has shifted by 3.7 degrees, and the main impact zone has deviated from the optimal force angle of the blades."

"ha?"

Simply put, the river no longer flows this way.

Chen Hao looked up at the river. The wind was still blowing, and the water was still moving, but it just wouldn't cooperate with his wheels. He sighed, plopped down on the muddy ground, and patted the spot next to him: "Come on, sit down and let's talk about life."

Nana didn't sit down, but she didn't argue either.

"You know... could we make something big? Just put it in the middle of the river and let it generate electricity for me every day, while I just lie there."

“Sure,” she answered readily, “but we need to figure out three things first: the riverbed’s load-bearing capacity, the structure’s erosion resistance, and whether you’re willing to go into the water for maintenance.”

"I can not swim."

"Then we'll lengthen the maintenance bracket."

Chen Hao grinned, as if he had heard some particularly reliable plan. He rolled over and got up, brushing the mud off his pants: "Okay, let's get to it! Now let's go pick a place."

"It is recommended to bring surveying equipment and a terrain terminal."

“I brought it.” He stuffed the terminal into his canvas bag, then casually popped half a compressed biscuit into his mouth, chewing as he said, “We call this going from dream to field investigation, all in one step.”

The two walked down the riverbank for about 300 meters before the terrain began to change. The left bank was noticeably higher than the right, with more rocks, a thinner layer of soil, and a layer of grayish-white hard rock exposed underneath. The river made a gentle bend here, the current became steady, and the water surface widened.

“This place looks alright.” Chen Hao stopped, panting. “The water is stable and the ground is firm, unlike that old mudflat where you could sink up to your knees with one step.”

“The initial assessment is too optimistic.” Nana opened her terminal and started an underground scan. A few seconds later, the screen lit up with a profile image: “The soil on the right bank is loose and shows signs of continuous erosion, having receded by an average of 1.2 meters per year over the past two years.”

That means—

"Three years from now, the original installation site will be located in the middle of the river."

"Oh." He paused. "Then it won't be generating electricity, it will be drifting."

"And the probability of structural instability is 86 percent."

"That high?"

"Based on simulations of historical flood season data, if there is continuous heavy rain, the risk of collapse increases to 94%."

Chen Hao stared at the red warning area on the screen, remained silent for a few seconds, and then asked, "Where can we build it?"

Nana swiped the map and marked a point on the opposite bank: "This is a gentle slope leading into the water, with bedrock depth of four meters, stable soil layers, and no significant displacement in the past five years."

"But that's far from the base."

"837 meters away."

"Not too much."

"Transmission losses increased by 15 percent."

"Wow, you're really good at calculating."

"This is basic logic."

He scratched his head and looked at the river again. The new location was indeed on the opposite bank, further upstream, with a straight current and no messy whirlpools. He clicked his tongue: "Okay, I'll do as you say. But I have one condition."

"explain."

"Could we add a diversion dam? To push the water towards the wheel, so it doesn't ignore us."

Nana brought up the fluid dynamics model, input the parameters, and ran the simulation for ten seconds. In the new design, a low stone embankment extends diagonally from the riverbank into the river, guiding some of the water flow to concentrate its impact on the blades. Data showed that the force efficiency increased by 22%, and the speed fluctuation decreased.

“It’s feasible,” she said, “but it will require an additional 1.8 tons of stone, extending the construction period by two days.”

"It's better than the wheels moving on their own in the future."

She nodded and began generating preliminary planning diagrams. The structure gradually taking shape on the screen included: main support pile foundations, an inclined upstream turbine, auxiliary guide dikes, and a bank-side transmission house. The overall layout avoided the main current impact zone and utilized lateral current drive, significantly improving stability.

“I recommend a pile depth of five meters,” she said. “It should penetrate the surface loose soil and anchor into intact bedrock.”

"Five meters?" Chen Hao's eyes widened. "Can you even dig that far?"

"A hot melt drill bit can be used in conjunction with a vibratory hammer."

"Do we have that kind of thing?"

"The inventory records show that there is one unit."

Where?

"B3 tool bay, status unknown."

"It's 'status unknown' again... Is this all the words you robots can think of?"

"Accurately describe the reality."

He rolled his eyes, lowered his head, and took a bite of his biscuit. A crumb fell onto the blueprint, and he flicked it with his finger, accidentally smearing a small patch of the data column.

"It's over, the site is contaminated."

"It does not affect the core parameters."

"That's good." He wiped his mouth. "So, is this design finalized?"

"First draft approved."

"Then I hereby declare the large-scale waterwheel construction project officially launched!" He stood up, stretched his palm into the air, "Come on, let's give each other a high five to celebrate."

Nana glanced at him and raised her hand.

With a crisp, clear snap.

He laughed like a fool.

Over the next few hours, they walked back and forth along the newly selected site three times, marking the stake positions, measuring the water depth, and recording the riverbed slope. Nana kept revising the model, adding new field data. Chen Hao was responsible for moving stones to test their weight and kicking the soil layer to check its hardness, while also complaining about the hot weather, sand getting into his shoes, and the compressed biscuits being too dry.

"Bring a bottle of water next time," he said. "Otherwise, my mouth will be split open like a map."

"The body's dehydration alarm has not yet been triggered."

"But I feel really bad."

"Subjective discomfort is not within the scope of emergency treatment."

"You robots are so cold-blooded."

"We are simply prioritizing addressing objective issues."

As the sun began to set, the survey was essentially complete. Nana synchronized all the data to the base's main system, preparing to return and draw up detailed construction sketches. Chen Hao sat on a large rock by the river, munching on the remaining half of a pancake while staring blankly at the drawings.

"You mean... this thing can really last for five years?"

"According to the current design, the theoretical lifespan is seven years."

"What if the water rises?"

"The flood control threshold is set at a water level that occurs once every 20 years."

"What if I'm lazy and don't fix it?"

"The structural decay rate is accelerating, and significant shaking is expected in the third year."

"The fourth year?"

"It may disintegrate on its own."

"The fifth year?"

"To become a floating art installation on the river."

He burst into laughter and almost choked on the pancake.

"Then you have to remind me to fix it."

Yes, it will.

"Don't wait until I'm dead to say 'I told you so'."

"Won't."

He dusted off his pants, stood up, crumpled the empty wrapper into a ball, and threw it into the river. The ball of paper floated on the water for a while before being slowly carried downstream by the current.

“Let’s go,” he said. “Let’s go back and draw up some plans. Let’s see if we can find that drill bit whose status is unknown tomorrow.”

Nana closed the terminal and followed him on the way back.

Halfway there, Chen Hao suddenly stopped.

"etc."

"how?"

He pointed to a point on the other side of the river at the newly selected site: "You said the pile foundations are to be driven five meters deep, so for the first hole... we need to test if the location is accurate first, right?"

"Pre-insertion testing with positioning rods is possible."

Do you have any tools?

"There are three metal probes in the workshop."

Did you bring it?

Nana turned to look at him.

He grinned: "Just kidding, I don't believe you weren't prepared."

She didn't smile, but she didn't stop walking.

The two continued walking, their shadows stretched long by the setting sun.

As they approached the base entrance, Chen Hao suddenly stopped again.

"Do you think... we can be considered to be doing proper construction?"

"The technical process is complete and meets the standards for project initiation."

"Should I start writing a work diary?"

"what ever."

How should the first sentence be written?

"I suggest starting with practical actions."

He thought for a moment, then took out his notebook and wrote down in crooked handwriting:

"I didn't lie down today. I walked 3,700 steps, surveyed the river, and installed stakes. I even got sunburned and my skin peeled. It's the first day of the large waterwheel project. I'm exhausted like a dog."

After finishing writing, he closed the notebook and put it back in his pocket.

In the distance, the lights in the workshop came on.