The magic mirror is not a transparent metal

One of the Star Trek movies has a McGuffin called "transparent aluminum". Although magic mirrors are not truly transparent, it appears that way to a casual observer. If you haven't seen any, these are polished metal mirrors with an embossed pattern on the back. However, when you shine a point light source on the mirror, the reflection is what is behind the mirror. Is it transparent? No, and [Steve Mould's] video below explains what's really going on.

The reality is that very subtle variations in the surface produce the image. You need some understanding of optics and calculus to fully understand what's going on.

The real mystery, however, is how these parts are made. There is speculation on the thickness of the embossment, but keep in mind surface variations are a fraction of a micron. What's even more interesting is that not all mirrors reflect the image on the back, which makes you think that the image on the back is just a subterfuge and not necessarily part of the process of manufacturing.

We believe that if anyone can figure out how to make them, it's our readers. We will accept any speculation other than using a 555 or an Arduino. We wonder if you could cast them in epoxy. We'll admit that optics aren't our forte, but we do dig into it from time to time. There is always a use for a Fresnel lens.