Code: The Hidden Language of Computer Hardware and Software, 2nd Edition

Chapter Five

Communicating Around Corners

You’re 12 years old. One horrible day your best friend’s family moves to another town. You email and text your friend now and then, but it’s just not quite as thrilling as those late-night sessions with the flashlights blinking out Morse code. Your second-best friend, who lives in the house next door to yours, eventually becomes your new best friend. It’s time to teach your new best friend some Morse code and get the late-night flashlights blinking again.

The problem is, your new best friend’s bedroom window doesn’t face your bedroom window. The houses are side by side, but the bedroom windows face the same direction. Unless you figure out a way to rig up a few mirrors outside, the flashlights are now ...