One cause for one effect; the kinds of factors that can produce a given type of injury are actually just a few.
Abrasions, blunt-force trauma, stab wounds...
All of these have very distinct ways they're made!
And the "finished product" that Zheng Shijie and his people made is something ordinary people could never get from any so‑called accident!!!
To put it this way.
At those rural "big fairs," the people who slide with their bodies laid out on flat carts—how twisted their bodies are is often downright horrifying!
For example, a severely twisted waist, bent backwards the wrong way, head tucked down between the thighs!
Seeing that, your first instinct is to think they fell, or something else happened, but if you really think about it...
What kind of accident could make a person's waist bend backwards the wrong way like that!?
Falling from a high school building?
Hit by a car?
An earthquake? Or some so‑called fire?
