A number of watches in every possible location, kitchen, shower, bedroom, corridor, and all of them are syncronised. You don’t ever need to control or update them. You can put an alarm clock or a timer, and the closest one would play, and the others stay silent. If you move, the melody moves with you, until you stop it.
Well, just ten or fifteen years later, and we almost there, and we call it ‘Smart Home’ these days.