The light blue paint on the side of the electric cargo tricycle body has been mottled, and the most conspicuous is a brown scratch extending from the door to the rear. Lao Li said that it was a "medal" left when he helped a moving company transport refrigerators last winter. The direction of the scratch perfectly coincides with the arc of the door handle. Whenever the sun shines obliquely, this scar will be like some mysterious rune, casting fine light and shadow on the car body.

The rearview mirror is a double-linked type that was added later. The left mirror is covered with mist-like water stains, while the right side is as clear as before. Lao Li explained that this is to allow passengers to see the road conditions clearly on rainy days, while the driver can observe the inside and the rear at the same time. This dual-perspective design is just like the role of this car in the city - both an observer and the observed.

When the front hood is opened, the exposed motor is like a beating heart. The light green silicone cable is wrapped around it, and every time it is started, it will emit a low-frequency "buzzing" sound. This is the breathing rhythm of the tricycle - 60 times per minute when stable, and up to 120 times when accelerating.

There are several dry maple leeaves stuffed in the heat dissipation holes on the side of the battery compartment. This is the "thermometer" left by Lao Li deliberately. When the maple leaves begin to curl, it means that the battery temperature is close to the upper limit and charging needs to be suspended. This primitive but effective monitoring method makes Lao Li feel more at ease than any electronic instrument.

There is a wavy line painted with white paint on the side of the left rear tire. This is the secret code between Lao Li and Lao Chen in the repair shop. When the wavy line begins to wear, it means that the tire needs to be replaced. The gravel and chewing gum residue embedded in the tire pattern record every alley this car has passed through.

The grease nipple on the wheel axle is a part that Lao Li must check every day. He modified a refueling machine with a discarded syringe. Every time he injected grease, it would leave a small oil stain on the axle. These traces are connected, like a miniature map, marking the movement trajectory of this car in the folds of the city.

In the maze of reinforced concrete, this simple Electric Tricycle is like a slowly crawling beetle. It has no streamlined appearance and no intelligent navigation system, but it measures the temperature of the city in its own way. Those ignored gaps and forgotten corners have become flowing scenery in its turning, bumping and stopping.