There is a part about these in Christophe Alexander’s "A Pattern Language: Towns, Buildings, Construction ". Worth a read.

Imagine if the Nazis built Auschwitz and the most complaints about it was that they did not torture people efficiently enough.

What a dark world we live in.

It’s how I learned it but it turns out… the most health benefit from tooth paste comes from not rinsing it out. The fluorides do better work that way. Also the main reason why you should brush 3 minutes. No mechanical or cleaning reason. It’s to keep the fluorides on them.