Step-by-step room sweep, lens optical retro-reflection strobe, two-way mirror gap test, and spy Wi-Fi prefix verifier.
Turn off all room lights. Tap below to pulse intense red/white light. Walk slowly facing suspicious objects. Any curved glass camera lens will gleam with an unmistakable pinpoint reflection!
Place your fingertip perpendicular to the mirror surface. Observe the contact point between your nail and its reflection:
Open your phone's Wi-Fi Settings and look for unpassworded or strange local hotspots with long serial numbers: