(Penny and Amy are going through wedding magazines)
Amy Farrah Fowler: It's just so hard to tell what will look good on me.
Penny Hofstadter: No. This is just to give you ideas. You know, do-do you want something simple and elegant? I mean, do you want a train?
Sheldon Cooper: Ooh, we're talking about trains.
Amy Farrah Fowler: Not the kind of trains you like.
Sheldon Cooper: Oh, I like all kinds of trains... steam, diesel, coal, elevated, bullet. I defy you to name a train that I don't like.
Penny Hofstadter: The kind on the back of a wedding dress?
Sheldon Cooper: I did not see that coming. Good job.