Two men are bragging about how to use their fan.
A: I can use my fan for 20 years.
First I open a fourth section and use it for five years.
And then, I open another fourth and use it for another five years.
And I repeat the same thing two more times.
B: Oh, that's wasteful.
I have a better idea.
I can use it a lifetime.
First I open it wide, and I hold it under my nose.
And I wave my head.