LED light bulbs are the future. They're better for the environment and the pocket book. But for some people, certain LEDs lights—particularly holiday lights—are also a problem. They flicker in a way that causes headaches, nausea and other discomfort. Today, we visit the "Flicker Queen" to learn why LEDs flicker—and what you can do about it.Wondering about other quirks of lighting and engineering? Email us at shortwave@npr.org – we might cover it on a future episode!