China: Inventor presents "hair-washing machine" after years of experimentation

There are people who have trouble washing their hair. They can't lift their arms, for example. Of course, someone would have to help them with this contraption the way it is now, but maybe he's still working on that part.

This being said, the shampoo cap is a thing that exists already. It is a disposable cap that has shampoo and conditioner in it. It is very simple to use and it's not messy. It doesn't come in a variety of shampoos, but when you're using shampoo cap, you are sick enough where you're just happy to have clean hair.