Also in Sweden no flats have numbers (like the rest of the world) only the person surname on the flat door. Thus finding the correct flat in buildings with different parts and courtyards is difficult especially when people have the same surname
One more also, I bumped into a food delivery guy at our building yesterday and he didn’t know where to leave the delivery… a simple system like this could help him to find the correct drop-off point especially in these times of social distancing