My son laid a fart.
"He broke wind!", thought his mother.
My son seems having a think of something.
Son: "Mom"
Mother: "... (Here he goes)"
Son: "How come farts go somewhere?"
Mother: "What?"
Son: "How come farts disappear?"
But, from the beginning, we cannot see farts.

Mother: "Have you ever seen them farts? I haven't seen them though."
Son: "Because when we eat sweet potatoes, we lay a poot! You know it!"

Right!
Sound also exists.
There is no boundary between existing and no-existing, or visible and invisible.
I get it!

Nonetheless, poot...