RAY: We have a friend, Tommy and I, who shall remain nameless, who works at a government facility and does very, very important work.

TOM: Yes.

RAY: And one day, he's at his desk working away, reading some very technical manual when he's awakened … I mean, startled by the sound of his stomach growling. He turns in his seat and looks at the electric clock on the wall behind him. This is one of these clocks that's been there for, like, a thousand years. It plugs into the wall.

TOM: Big analog round thing.

RAY: Right. He looks at the clock, and as he turns back to his work, he says, "Well, it's obviously too early to eat lunch. I must have forgotten to eat breakfast." He begins to work. A short time later, he's again awakened, startled, by the growling of his stomach. And this time, he turns to look at the clock another time. You with me so far?

TOM: Yeah.

RAY: He looks at the clock another time, and he notices that it first of all says a time later than what it did the first time he looked at it. The second hand is sweeping. The hour hand has moved from where it was the last time he looked at it, and the minute hand is in a different position.

TOM: Mmm-hmm.

RAY: And as he turns back to his desk, again thinking that he must have forgotten to eat breakfast and he doesn't know how he's going to make it to lunchtime, his stomach growls a third time, and he says, "The clock is broken." And yet, everything seemed to be working.

TOM: Yeah.

RAY: Now, I may have to give a hint. The question is: How did he know the clock was broken?

TOM: Well, the minute hand, the second hand and the hour hand have all moved, you said.

RAY: Yeah. The two hands are exactly 180 degrees apart, like they would be at 6:00. That's the hint I was going to give.