Wow! And high praise for the Oscar Holland, who linked exactly the correct research article to describe the optics of this style of "magic mirror": https://www.researchgate.net/publication/231068500_Oriental_...

This also features in Ken Liu's Dandelion Dynasty series.

Here is the modern version of "Magic Mirrors: How To Make Reflection Art"! [1]

And, here is a modern method to make magic mirrors that reflect, similar to the artifact, "HOW TO MAKE A MAGIC MIRROR" [2]

[1] https://babbledabbledo.com/magic-mirrors-how-to-make-reflect...

[2] https://www.constructedadventures.com/how-to-build-a-treasur...

Reflections are easy geometric transformations. I think in this case it's about inverse geometry, which is much more difficult to perform https://en.wikipedia.org/wiki/Inversive_geometry

EDIT : another comment here suggest it's even more complex, using Laplacian

I can’t find much else on these. I wonder if the technique has been rediscovered as the “scratch hologram”:

https://forum.lookingglassfactory.com/t/incredible-scratch-h...

Probably not, although scratch holograms are really cool. It looks like it's a fundamentally different mechanism

Researching this, looks like it's called https://en.wikipedia.org/wiki/Specular_holography

This is the plot device of "the Vivero letter" by Desmond Bagley written in 1968

Argh! Spoilers! /s

Very cool and completely new to me. Thanks for this!

It absolutely is an image. There are multiple definitions for an image - from a graven image in the Bible to a heroic image in sculpture or even to an image in someone's imagination. You are using a definition of a photographic or computer reproduction as the sole definition for the word image. That's not correct.

Visual artworks are images. Here are the first three definitions of "image" I just found:

- a representation of the external form of a person or thing in art. [Google]

- a visual representation of something: such as (1) : a likeness of an object produced on a photographic material, (2) : a picture produced on an electronic display (such as a television or computer screen) [Merriam-Webster]

- a physical likeness or representation of a person, animal, or thing, photographed, painted, sculptured, or otherwise made visible. [Dictionary.com]

Pedantry doesn't suit you.

Especially when it's incorrect pedantry.