We had such a system (with only one pipe) a few decades ago in our company. Purpose was to deliver samples from the production to the laboratory. When I started in the late 90’s it was already not in use anymore. I got told that sometimes the pipe got clogged…

Seems commenting works. At least for me.

I know exactly what you mean. I live since 10 years in #China and it is unbelievable what people think when they have no access to independent news. Even if they got access after some time, they’re not going to believe it, because it’s so different from what they got thought the reality is.