Visual anagrams popped up last year using similar, though simpler methods to those in the posted. Flips, internal rotations, rearrangements, color negatives etc.
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Diffusion illusions did something similar at about the same time but with puzzles and multi-image color layer mixing. Some of the double puzzles they made are a lot of fun. They have great explainer videos [1] on that site including with Steve Mould.
Also there are diffusion double/hidden images using qrmonster, illusion diffusion, control net, or img2img that have been making the rounds. [2] for a random example. These work by using a fine-tuned diffusion model[3] to take an image and use it as a structuring element at various levels of following to a generated image. To see these illusions, squint or move the screen away. These are quite a bit more popular and easy to make than the other methods so many more examples show up around the internet.
