Optical illusions

Are you starting an optical collusion?

optical seclusion?

That is straightforward. But I don't know why you call it one of the best.
I ever watched an optical illusion in a town of China: Girl's head with a snake's body. Girl's head opened her mouth talking to me. I don't know there is such an optical trick in US. It is good. Still, I would not have called it one of the best.

This is the architectural optical illusion in Melbourne, Australia alluded to by Cicerone Imposter at the top of this thread. The horizontal lines appear slanted, but they are parallel.

https://www.youtube.com/watch?v=vhz2XQoowuc