Wifi can read through walls
Using wifi for spacial analysis has been an idea tossed around for years. MIT has researched this and found that WIFI can be an effective tool to locate motion in rooms and even reveal building layouts. New research being done now shows that wifi can even be used to read letters, even through walls. While this technology is still in early stages, it will no doubt have uses in espionage and intelligence gathering. https://news.ucsb.edu/2023/021198/wifi-can-read-through-walls