Alicey: Mattgreeeeeeeeeeeeeeeen! We have to go to High Wycombe before my birthday!
Mattgreen: Why?
Alicey: Because I need to get my tattoo redone.
Mattgreen: Why?
Alicey: Because I had it done when I was 17, and now I'm 34, so as long as I get it done before my birthday it will have been exactly 17 years!
Mattgreen: (looks at me strangely)
Alicey: I reckon it needs redoing every 17 years! In another 17 years I'll be ... (scrunches up face in concentration) ... er...
Mattgreen: Come on now, don't you know your 17 times table?
Alicey: Fifty-something!
Mattgreen: Fifty-one.
Alicey: Yes! I shall be fifty-one. By then I'll probably want to have it removed.
Mattgreen: You'll be able to get that done on the internet by then.
Alicey: Or I'll just be able to stick my arm up against a panel on the wall and it'll go "Nnnnnnnnnnhhhr" and it'll be gone!