Super Spy Decoder
We’ll see that if we make the right choices, we can make a secret message decoder. The secret message will be written in a color that can be seen through the filter, while the rest of the image is made using colors that are obscured by the filter.
A bunch of colors with three choices of plastic colored filter films.
We will learn that in an anaglyph, you have two copies of an image, offset a bit, where each eye sees only one of the two. The decoder example hints at how we will achieve this:
