The first is the treadmill, which is a punishment tool invented in ancient times. Most people commit crimes and will be arranged to run on the treadmill in their cells. This running is certainly not as simple as everyone thinks. Sometimes there are some nails on the treadmill, and you have to keep running on them. Of course, it must be a long time. Sometimes it takes hours to run. If you don't act, someone will whip you behind your back. This punishment is really terrible.
In addition, the operation opportunity is directly connected to the national hydropower system, so that these people can use it for work while providing a lot of energy, which really kills two birds with one stone.
Who would have thought that the way of fitness that young people like so much now was actually a punishment in ancient times. Treadmill was probably the favorite thing for young people to go to the gym now, but in ancient times, prisoners in prison just wanted to shudder at the sight of treadmill.
Besides, I also want to mention high heels. In ancient Europe, high-heeled shoes were invented for men, because in ancient Europe, all men had to learn to ride horses, and short men couldn't touch the saddle when riding, so they invented high-heeled shoes, which not only made them look tall, but also increased a lot of masculinity, at least it was much more convenient. This is really an invention that kills two birds with one stone.