Criminal Minds2005

Diane Turner:
There was a moment when you had him, and you knew you had him. What was it?

Dr. Maeve Donovan:
Euclidean geometry. There's this thing called the Penrose triangle. He told me a story about how he tried to build one when he was eight.

Diane Turner:
This better get sexy quick. I'm getting bored.

Dr. Maeve Donovan:
You can't build it. It's an impossible physical structure. It only exists in conceptual geometry. But I said, every Penrose triangle has its thorns. He laughed. It was a stupid pun, but he laughed.

Diane Turner:
That's it.