A small object A is located between the fixed converging lens and a fixed plane mirror perpendicular to the main optical axis of the lens. Here lens of focal length f will make two images of object A namely $B_1$ and $B_2$.The lens shall also make its own image due to the plane mirror namely C. Both images of the object A  ($B_1$ and $B_2$)have the same dimensions, regardless of the distance from the lens to the object.