 If you hear the signal, you shoot the gun. Only shoot the gun if you hear the signal. What will the signal be? Three pulses. Right. A letter S. Three pulses. Can we go now? I'll be timing everything, so shoot the gun right away, but only if you receive the signal. An S. Got it. Are we ready, gentlemen? Okay, I'll start the clock on a countdown from three. And you're sure I won't get electrocuted? Tres, due, uno, go!