A few of the lights in the apartment have a remote control dimmer. This is great in theory, but one remote can control all of the lights. So, say, if Sarah turns off the lights in the living room, I might find myself in the dark in the computer room as well.

But it gets more complicated if the lights get out of sync. If the lights are on in the living room but off in the computer room, turning them off in the living room will turn them on in the computer room. And vice versa.

Getting them back in sync becomes a minor brain teaser (like getting a fox, a chicken and a bag of feed across a river in multiple trips on one boat). "Okay... if I turn the light in the computer room off using the wall switch, then turn the lights in the living room on using the remote, then turn the lights in the computer room back on using the wall switch, they should both be on, right?"

Or maybe we should stop using the remote control.