If someone is trying to go heads-down, then can let other people know (or maybe use a do-not-disturb sign / flag or similar), but I think of it more as somethin

If someone is trying to go heads-down, then can let other people know (or maybe use a do-not-disturb sign / flag or similar), but I think of it more as something you would do when you're in the mood for possible engagement/interruption rather than just straight working; in cases where you wanted to be sure you'd not be interrupted, there's always regular co-working spaces/your apartment/regular coffee shops. This would be more for "I'm working, but not so intensively that you can't talk to me" times.