Time-sharing
Making one floor do several jobs at different times — a living room that becomes a full bedroom at night, then a full living room by morning. The core of the Layer lever, and stronger than space-sharing because each function gets the whole space, uncompromised.
One floor, many hours
Your bedroom sits empty all day; your living room all night. Overlay them in time and one footprint quietly becomes two rooms. Three functions time-shared can need ~45% less floor than three separate rooms.