Xiang Kun's apartment was only seventy square meters, with two bedrooms and a living room. The balcony was small—narrow, even.
One thing it had going for it was the decent view. The neighboring high-rises were far away, and he could see the mountains in the distance.
Xiang Kun didn't bring out a chair. He simply lay down on the balcony tiles—after carefully wiping them clean, of course.
Under the night sky, Xiang Kun felt particularly good. His physical functions were at their peak, and his sensory abilities had improved tremendously after targeted training and further mutation following his last three blood-drinking sessions.
But with the equipment available to him, he couldn't perform accurate tests or gather statistics. He'd downloaded an app that could play sounds ranging from 1 to 22,000 hertz, but that could only test the range of frequencies he could hear. It still couldn't fully measure the overall improvement in his hearing. He'd also tried using a fixed sound source as a reference, moving farther and farther away and judging his hearing by the maximum distance at which he could still hear it. But that method required a relatively stable, controlled environment, was easily affected by interference, and was difficult to measure accurately.
His sense of smell was much the same. All he could do was make rough, subjective assessments.
Lying on the balcony tiles, Xiang Kun closed his eyes and relaxed his muscles, focusing all his attention on his hearing and sense of smell, prioritizing hearing and using smell as a secondary sense.
Sounds surged toward him like floodwaters released from a reservoir, overlapping in a jumble. The smells did the same.
The human brain had a well-developed system for processing information from the outside world. It could be called a protective mechanism, or a way of taking shortcuts.
When a person wasn't paying attention to sounds or smells, the brain weakened, filtered, or even blocked the information gathered by the ears and nose.
But when attention was focused on sounds or smells, the brain could concentrate and amplify the transmission of the information it was focused on, blocking out other distractions.
Still, hearing a sound or smelling something, and identifying a sensory signal, was one thing. Using that signal to make a judgment was another.
For instance, someone sitting at home might hear a car roar past outside.
If the sound caught his attention, an image of a car speeding along the road outside would instinctively appear in his mind.
That image was possible because he was familiar with the road outside, had heard cars, and had seen them racing down it.
Someone more familiar with the sound of engines and exhausts might even be able to tell whether the car outside had a four-cylinder or six-cylinder engine, whether it was a Ford or a Toyota, a beat-up diesel truck or a supercar. The image in his mind would be more vivid and detailed, too.
If the person sitting at home heard the crisp patter of high heels upstairs, he'd recognize the sound as a pair of heels. If he'd never seen the upstairs neighbor, he might picture a young woman with long legs walking around in them. But if he knew the neighbor upstairs was a fifty-year-old woman, then he'd imagine a fifty-year-old woman walking around when he heard the heels.
The brain filled in the blanks as needed, drawing on its "database," experience, logic, and instincts.
So being able to gather sensory information was one thing. Whether that information could actually help the brain make a judgment was another.
Xiang Kun had chosen to lie directly on the floor not because he couldn't bring out a chair or lay down a blanket, but because in a building made of concrete and steel, sound traveled primarily through the air, walls, and floor. By lying down and making direct contact with the floor, he could hear the sounds of the entire building more easily.
As he listened to the jumble of sounds, Xiang Kun carefully distinguished and filtered them, starting with the ones closest to him. First came 608, the apartment directly below. From what he could hear, a middle-aged couple were talking about their son, who was attending university up north, while the evening news played on the television.
Next, the apartment beside his was completely quiet. There were no footsteps, appliances, or voices, and he couldn't hear anyone breathing. But he could hear curtains fluttering in the breeze. The windows must have been closed, and the owner hadn't returned.
Then he heard the voice of Little Chubby Girl, Liu Shiling, whom he'd seen during the day. He pinpointed her location as 706—he knew her family lived there.
From the sounds, Little Chubby Girl and her mother were home. Her mother was urging her to go take a bath, while she stayed glued to the television, unwilling to stop watching cartoons.
Using 706 as his point of reference, Xiang Kun continued to distinguish the sounds he heard and draw conclusions.
When he heard footsteps, he could use the layout of his own apartment and other reference sounds—like a running faucet, a gas stove lighting, a cup being picked up, or an appliance being switched on—to determine where someone was in their home, and even which way they were moving.
He could also use smells to help. For example, if he heard the clatter of a spatula and food being stir-fried in 402, then matched it with the smell, he could figure out what dish they were making—and even get a pretty good idea of how it tasted.
Smells and sounds could also confirm each other, helping him pinpoint locations more accurately.
Time passed bit by bit. From the outside, the lights throughout the complex gradually went out, and the sounds and activity from each apartment slowly died down.
It was past one in the morning when Xiang Kun finally opened his eyes, sat up, and stretched.
Using sound and smell, he'd "visited" every apartment in the building and followed the activity in each one. He'd only actually met, exchanged names with, and gotten to know one person so far: Little Chubby Girl Liu Shiling in 706. But over the course of the night, he'd practically gotten to know everyone in the building through sound and smell, and had even learned quite a few "secrets."
Of course, Xiang Kun wasn't doing this to pry into people's private lives. He was training.
Just as he'd shifted to training his endurance and agility after building muscle, now that his sensory abilities were improving rapidly, he needed to train his brain to process the sensory information he received.
Two professional athletes might weigh the same and have similar amounts of muscle, but because they played different sports and trained differently, they'd use their strength in different ways, with different results. A professional boxer would naturally punch harder than a professional basketball player, while a basketball player would certainly be better than a boxer at performing basketball moves under the same level of physical pressure.
So Xiang Kun knew that simply having stronger senses wasn't enough. He still needed to practice and learn how to use them.
The first stage was to gather "samples" of sounds and smells he hadn't encountered before, building a "database" that would become second nature to his hearing and sense of smell. He'd already completed most of it.
The second stage was what he was doing now: learning how to use sounds and smells to assess his surroundings and what was happening in them, turning them into his "super vision."
At the moment, it took him five or six hours to "visit" the entire building. But once he was familiar with it, perhaps he'd be able to locate anyone in the building from sounds and smells in just a second or two, even building a real-time, holographic image of the entire place in his mind.
Xiang Kun had already discovered that as his senses evolved, his brain was evolving too. At the very least, when he immersed himself in multiple sounds at once now, he no longer felt nauseous or dizzy like he had at first.
At seven thirty the next morning, Xiang Kun headed out with his gym bag, planning to go to the gym. It was a long way from his new home to the gym he'd been going to; he'd have to take the subway and then a bus, which would take at least forty or fifty minutes. But he didn't plan to switch gyms. He'd already paid for the membership, and there was no getting his money back.
Besides, he didn't plan to take public transportation. He was going to run there instead. The run itself would be part of his training.
As he left, Xiang Kun happened to see Liu Shiling from 706 coming out, too. Behind her was a plump young woman who looked quite a bit like her—probably her mother.
"Bald Uncle!" Liu Shiling called as soon as she saw Xiang Kun, then ran over to greet him.
Her mother immediately looked embarrassed and hurried over. "Oh, I'm sorry. She's just a kid—she doesn't know better and calls people all sorts of things. You're the new tenant in 708, right? We'll be neighbors from now on. If you ever need anything, just let me know."
Little Chubby Girl ran to press the elevator button while Xiang Kun chatted with Shiling's Mother. He learned that they'd only moved into 706 this year, after buying the apartment. Liu Shiling's father worked in construction and was often away, while her mother was a full-time homemaker whose main job was looking after their only child.
Xiang Kun gave a brief introduction of himself, saying that he was a programmer and had been working for seven years. He didn't tell her that he was currently unemployed.
They didn't have to wait long. Each unit in the building had two elevators, and one was soon on its way down.
With a ding, the elevator doors opened—and a dog's head poked out, poised to lunge. Liu Shiling, who was standing in front of the elevator and about to enter, jumped in fright and stumbled back two steps, nearly falling. Xiang Kun quickly reached out and steadied her.
When he turned around, he saw a woman in her twenties holding the leash of an adult husky. The dog was clearly excited and tried to rush out as soon as the elevator doors opened. The woman had been using one hand to play on her phone and had nearly lost her grip.
"Pinkie! Pinkie! Stop! Stay!" the woman shouted, grabbing the dog's leash with both hands.
But the husky kept trying to get out. The little girl outside the elevator had clearly been frightened. She looked timid and clung to Xiang Kun's leg without saying a word.
Shiling's Mother clearly knew the woman with the dog. Frowning, she said, "Ms. Yang, you need to keep your dog under control. The elevator's such a small space, and the dog's so big while the child's so little. What if it bites or knocks her over..."
Ms. Yang held the dog and didn't even look up. "It's fine. Pinkie just wants to play with the little girl. She won't bite. I've got her leash! Pinkie! Stop! Sit! Sit!"
Shiling's Mother had clearly complained to Ms. Yang before and knew it wouldn't do any good. She pressed the elevator button and said to Xiang Kun, "You two go down first. We'll take the next one."
But Xiang Kun took Little Chubby Girl by the hand and led her into the elevator.
Little Chubby Girl was still a little scared and reluctant to go in. But the husky, which had been so lively and eager to lunge just moments before that Ms. Yang could barely hold it back, had now suddenly retreated behind her. Its head was pressed against the elevator wall, and it even seemed to be trembling.
Xiang Kun turned to Shiling's Mother and said, "It's fine. Come on in, too."
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