Detecting whether or not a mirror is single- or double-sided is a useful ability for varied causes. Double-sided mirrors, also called two-way mirrors, have distinctive properties that distinguish them from common mirrors.
One of many defining traits of a double-sided mirror is its skill to permit mild to go by one facet whereas reflecting it on the opposite. This property makes double-sided mirrors helpful in functions the place commentary is important with out being detected, reminiscent of in interrogation rooms, surveillance, and safety settings.