So... does this blue circle go away eventually? Been a few minutes and I still can't look at a white surface without seeing a clearly defined blue circle...

Yes, it goes away. But it may take a little while.

That Skytopia thing is crazy, you definitely need to stare for the full minute to get the effect though.

Also, any time I do these afterimage experiments I notice that my eyes are not very well aligned.

Yeah, I was rather astonished the first time I tried it. I expected it to be unconvincing, but nope, that is definitely a brand new shade of cyan.

Wauw, this is a whole new HN - does it come as a Chrome extension ?

It just works!

Ow.