Sensors and building automation systems are analogous to the central nervous system, providing feedback for the occupants and the building's own internal systems. This goes beyond just displaying information (signage) and delves into active response and adaptation. They detect changes in temperature, occupancy, or light levels and trigger responses like adjusting the HVAC, lighting, or security systems. Combined with the immune system, the building's healing, cleaning, and defensible space measures such as an HVAC system or earthquake-safe foundations, these systems are critical for proactive maintenance and preventing costly downtime. Much like a cardiovascular system, the building maintains a flow of water, waste, energy, and even people within the building. Efficient movement of these "nutrients" is crucial for the building's health and functionality- however, rather than a building eating people, its envelope and interior spaces stem from its program, a brain and (exo)skeletal system that dictates the building’s form and function, guiding and growing throughout its development and supporting its life-sustaining measures.