PASADENA, Calif. — Flippy, the burger-flipping robot that threatens to supplant short-order cooks, has taken its first extended break. But the burger maker isn't blaming balky robotics for the snafu.

In dangerous situations, finding help isn't always as simple as asking for it. From hand signals to coded 911 calls, instances of discreet signaling and coded language have gone viral in the past, and ...