The phrase ‘optical illusion’ usually (but not always) refers to a static image that is designed so as to highlight particular quirks of our visual and perceptual mechanisms. For example, an optical illusion might show us that our judgement as to whether or not two lines are the same length can be influenced - and thrown off - by surrounding perceptual cues (or intentional mis-cues). There are of course hundreds if not thousands of different optical illusions, and you can find them easily enough all over the web.
What you seem to be asking about, remisser, is something that works in a slightly different but related way, and is essentially about disguised or scrambled information. When you look at the item one way it reveals very little information, but looking at it another way with some sort of additional viewing device or mechanism reveals much more information.
I am not aware of anything that I would describe as an ‘optical illusion’ that works in this precise way, although there are many wherein what you see as a ‘first impression’ gives way to the awareness that the image actually contains far more detailed ‘covert’ content or is actually ambiguous.
However, I can list a few things that may approximate what you’re after.
(1) Magic Eye images. These appear to contain no information or ‘image’ at all except a bizarre pattern of repeated elements. When you learn to view them correctly, the brain can process the image to ‘perceive’ a three dimensional shape ‘concealed’ or ‘encoded’ within the pattern. ‘Magic Eye’ is a trademark, I think, but the term is widely used. Google is your friend. It’s harder to find the information you need to make your own, although you just have to dig a little deeper.
(2) Random dot stereogram. This consists of two squares, side by side, each of which appears to be the same random pattern of black and white dots. However, when you fuse them together with your eyes, you perceive some of the dots as floating higher than the base plane, and some of them as lower. In this way, some useful information can be ‘coded’ into the RDS. It’s easy to make these. Google away!
(3) Mirror writing. If you just write a message backwards, it is fairly obvious (to anyone who reads and writes the same language) that it is mirror writing, and that to read the message properly it is only necessary to hold the text up to a mirror (or just work it out in your head). However, if you take a simple line of text, write it in a slightly distorted or ‘jazzed up’ way, mirror-reflect it and then embed the text in a larger pattern or design intended to disguise the fact that there is any writing there at all, you can achieve an image that doesn’t look like itcontains a message at all. However, when you hold it up to a mirror, the text tends to ‘jump out’.
(4) Colour filters using dilute inks. Create any random or distracting design you like, the more fine details the better, using predominantly red ink. Take some green ink, and make a dilute solution of it (e.g. try one part ink to five parts water at first , and experiment from there). Take a paintbrush, and paint your secret message or image on the red pattern with the dilute green ink solution. Let it dry. When you look at the result usuing normal vision, you won’t see much if anything of whatever you wrote or drew using the dilute green ink. Look at it through a red-tinted lens, however, and the green ink message should appear fairly conspicuous. It takes a lot of experimentation to get this to work satisfactorily.
(5) Polarising filters. It is possible to create artwork and use polarising filters such that when the nearest filter is in one position you see one thing, and when it is rotated 90 degrees you see something different. There are places where you can buy inexpensive polarising filters printed on plastic, and experiment with them yourself.
(6) Mosaics. You can create both mosaic and pixellated images that don’t seem to contain any information close-up, but when you look from a sufficient distance away you can see that they are a portrait or a recognisable scene. It’s easy to explore this in Photoshop, and there are many examples online. To see this kind of artistry taken to its limits, Google the name ‘Frank Knowlton’.
(7) Ambigrams. Pieces of artwork or text designed so that they can be read in two or more distinct ways. Google on ‘ambigram’ or ‘Scott Kim’.
That’s all I can suggest for now. Good hunting.