Wow, this is great!

I want to put some of them in my UIs.

These are all super dark, for some reason.

This is cool, but more as a demonstration of interesting CSS techniques than optical illusions in my opinion.

Also, interestingly, I seem to be able to force myself to "see through" all of these illusions except for induced gradients, which I can't stop seeing unless I cover part of the screen.

33 - color fan: There is another interesting optical illusion here: The fan seems to rotate faster when not directly looking at it.