If you get a moment could you try an experiment

[OwlHoot]

Take a look at the image of a Poincare Disk in the middle of this blog article, and post to say whether or not the tracery in the middle seems to arch up slightly from the background in a sort of 3D effect. Try looking at various distances.

It does to me, but someone I showed it to said it just looked flat and nothing out of the ordinary.

Thanks in advance.

[Troll]

Take a look at the image of a Poincare Disk in the middle of this blog article, and post to say whether or not the tracery in the middle seems to arch up slightly from the background in a sort of 3D effect. Try looking at various distances.

It does to me, but someone I showed it to said it just looked flat and nothing out of the ordinary.

Thanks in advance.

Slight illusion of looking down on a convex lens type thingy

[Paddy]

Not an illusion as such and it will depend on the person. The colour receptors at the back of the eye are set at variable lengths for red, blue and green. (Similar to the colour layers on photographic film.

The light falling on the back of the eye via the lens will focus differently for each colour (like a prism) .

Variation in eye structure from person to person, including the factor if it you ware spectacles and if you eyes have a any prismatic correction will effect the “illusion” of a 3D when more than one colour is used

[Troll]

Not an illusion as such and it will depend on the person. The colour receptors at the back of the eye are set at variable lengths for red, blue and green. (Similar to the colour layers on photographic film.

The light falling on the back of the eye via the lens will focus differently for each colour (like a prism) .

Variation in eye structure from person to person, including the factor if it you ware spectacles and if you eyes have a any prismatic correction will effect the “illusion” of a 3D when more than one colour is used

You're not an Optician are you ?

[Paddy]

You're not an Optician are you ?

No, just got real bad eyes.

[ContractIn]

Take a look at the image of a Poincare Disk in the middle of this blog article, and post to say whether or not the tracery in the middle seems to arch up slightly from the background in a sort of 3D effect. Try looking at various distances.

It does to me, but someone I showed it to said it just looked flat and nothing out of the ordinary.

Thanks in advance.

flat as a pancake

[Paddy]

flat as a pancake

Buy some Quality Street. Put green wrapper on left eye, red on right eye.

[Sockpuppet]

I've had too many people try and send me the "stare at this image .... etc" oh...boo and scray face and a scream! So now I just don't bother.