Sheldon: Well, if I'm being honest, I never forgot about string theory. It's remarkable. It's the closest we've come to a theory of everything, something even Einstein couldn't figure out.
Penny: Well, if he couldn't figure it out, maybe it's just wrong.
Sheldon: But it's so elegant. I mean, look, [drawing on his white board] string theory posits that the fundamental particles we see in three dimensions are actually strings embedded in multidimensional space-time.
Penny: Interesting. So that would mean ... that [silence] ... Can't do this by myself, buddy.