Ever wonder why mirrors reflect left and right but not up and down? In other words, why does the mirror image of text appear backward instead of upside down?
The negative z-axis extends into the mirror image world. For any point (x, y, z) in the real world you can find the corresponding point (x', y', z') on the far side using these equations, suitable even for the mathophobic:
x' = x
y' = y
z' = -z