The boy: Aunty, what’s this stuff on the wall?
Auntie: It’s plaster.
The boy: What’s plaster?
Auntie: Go ask Grandad.
The boy walks outside. Grandad is sitting in a lawn chair under the walnut tree.
The boy: Grandad, what’s plastered?
Grandad: That’s when you have too much to drink.
The boy is very confused: Why would you put that on your walls?