Keep staring at the cross but try to be aware of what the faces look like in your peripheral vision. I think closer is probably best but experiment till you see something interesting. You can look straight at the faces for the next cycle or two if you want - it doesn't affect the illusion.
This all reminds me how utter shite our vision really is and how much we can thank our brains for assuming it's better.
The color bars work because our color resolution is way worse than our luminance resolution and so the colors bleed over into each other while our luminance and edge detection says there's hard lines. If you zoom in really close you can see the blue tinted green for what it is, if you zoom out a bit more the spirals become obviously different. This is part of how JPG compression works. It separates out the luminance from the color and then throws away a ton of the color since it's not really needed for proper perception of the scene.
It really is a cigar? That someone has carefully lined up with the gaps in the bricks?
I'm not sure that's an illusion. It's just what I saw. (I see the article goes on at some length about how it's an illusion even though some people say "meh". But I'm continuing to say .)
I was trying to zoom in (enhance! enhance more!) to see if it was actually a snek peeping out of a rusted iron pipe.
It really is a cigar? That someone has carefully lined up with the gaps in the bricks?
I'm not sure that's an illusion. It's just what I saw. (I see the article goes on at some length about how it's an illusion even though some people say "meh". But I'm continuing to say .)
I was trying to zoom in (enhance! enhance more!) to see if it was actually a snek peeping out of a rusted iron pipe.
Ah so you did see it at first. The illusion is that some folks don't see the cigar at all when they first see the picture. I did not. It just looked like bricks with a gray pebble stuck in between two of them. Until I saw the second picture in that article. Now that I saw that picture all I can see is the cigar. So not really interesting if you see the cigar right away.
Like many of the two image illusions like this I can get it to flip back and forth by thinking about what it's supposed to be, so even though I know what it is, it becomes an indent in the brick if I think "this shading is indented brick like those next to it and a grey turtle head popping out."
It's clearly a snapping turtles head and not a bird.