How does a one-way mirror work and what is its principle of operation?

A one-way mirror, also known as a two-way mirror, works by allowing light to pass through from one side while reflecting light on the other side. This effect is achieved by having one side of the mirror brightly lit and the other side kept dark. The principle of operation is based on the difference in light levels on each side of the mirror, which creates the illusion of transparency from one side and reflection from the other.