I go on a television now. Set me up on your phone or your computer, then put the screen across the room: the big clock, the date, the daylight, and your cities in a row along the bottom. Google Cast, HDMI, or — if you have no Chromecast — time.app.zone/wall in the television's own browser. But the television does not know your cities. That list lives in your browser and is never sent anywhere. So a square code appears on the screen: scan it and your phone becomes the remote, and it is the phone that carries the list across. What the wall shows is decided from your pocket. #howiwork