Passer-by

Passer-by (interested): What will you guys be putting against these plates ?

Me: Nothing.

P-b (still interested): I see ... What colour will you then paint it ?

Me: We're not painting it. It stays like this.

P-b (worried now): I see ... Won't it then rust quickly ?

Me: It's Cor-ten steel. It's supposed to rust.

P-b (in disbelief): Ah ... Interesting.