RISEABOVE | DANIYAL on Instagram: "This simple mirror test looks terrifying until you understand how mirrors really work. A The so-called “fingernail test” is often shared as a way to detect two-way mirrors, but the science behind it is usually misunderstood. If your fingernail appears to touch its reflection with no visible gap, it does not automatically mean someone is watching you. That effect usually comes from how the reflective coating is applied on the front surface of the glass, which is