Reflects rays originating from the front of the mirror (i.e., $P_1$) such that the reflected ray forms a directed line segment with a collinear point behind the mirror (i.e., $P_2$)
Reflects rays originating from the front of the mirror (i.e., $P_1$) such that the reflected ray forms a directed line segment with a collinear point behind the mirror (i.e., $P_2$)