What word can you read below?
There are in fact two words here: "victory" in black, and "defeat” in yellow. There are many more interesting examples like this. Here is another good example:
Look closely, and you’ll not only see the word “optical,” but also the word “illusion.”
This is a letter word-based version of the multi-stable perception Gestalt effect seen in the illusions of the Hidden Animals.
Abstract illustrations or objects like these appear unstably between one form of interpretation and another. The Gestalt theory, unfortunately only takes into account that this phenomenon occurs, but does not provide neurological explanations for why this is so.