I didn't mean to suggest that exactly the same thing was going on; just that it was analogous: it's possible to have the perception of motion without there being any motion going on. There's no consistency checker in the human perceptual system to keep that from happening.

I suspect that's why optical illusions are so fascinating to some of us — they demonstrate that our perceptions don't implement the law of non-contradiction. The snakes illusion is just a quick way to demonstrate this in humans who aren't in a religious ecstasy or on psychedelics.