Yes - in my case my brain told me with flat out certainty not that there was a cue there I couldn’t see right now, but that the table was absolutely, definitely empty. The space where the cue should have been (and actually was) wasn’t blank - it had been filled in with fictitious green baize to present a totally coherent image. It does make you wonder what else your brain is lying to you about right now.
But only for a second, and then my brain assures me everything’s fine.
Related to the ‘cocktail party effect’ I suppose. That’s where you can maintain a conversation with someone in a noisy room full of people talking (and someone’s bad choice of music playing too loud on a stereo at the same time). In this case it’s not advantageous since your brain is piecing together information that doesn’t add up to anything.
“General Washington, I have finished our nation’s flag.”
“Betsy! You fucked it up!”
There’s another brain-image-processing tidbit for you: That page has a lot of different color-reversed flags on it, that look like they have a wide variety of different color schemes. Their antagonist colors would, logically, have just as much variety to them. But all of the antagonists of those flags, in all their variety, would all be recognizable to the viewer as “correct American flag colors”.
Are you saying our brains are making us “see” something different than what our eyes are picking up? Cool!
I think it’s more that what appears to be a narrow band of colors that fall within “red” or “blue”, when reversed, look like a wide variety of “teal-blue” and “yellow-orange”.
I notice this frequently in concerts when they are using red and blue spotlights on the stage. It’s called chromostereopsis.
I have derived endless amusement from the Magic Eye effect that tiled restroom walls provide (And LSLGuy refers to). Well, in recent years anyway. Once upon a time I didn’t stand there long enough to notice.
My other frequent optical illusion is also bathroom related. Not long ago, changing out a roll of toilet paper, I had occasion to think, “huh! Now, why would they change the diameter of the inner cardboard tube?” The tube in the old roll was clearly larger than the tube in the new roll.
A few days pass. Again I am changing the roll. Whaddaya know! The tube in the new roll is once again smaller. Apparently the larger diameter of the paper surrounding the roll (the usual couple of inches vs. no more than a quarter inch) caused the central circle to seem distinctly smaller.
Until I held the tubes end-to-end, I would have sworn there was a size difference.
After reading my Kindle for a couple of hours, the sun was shining through the adjacent window and I closed my eyes.
The weird thing was that I could see lines of type on the inside of my eyelids but I couldn’t make out the words. I “think” it may have been reversed - that is each letter as a mirror image but not the whole words.
Thanks for the link, I put it down to mybad eyes, now I can say why they are bad, at least in that respect 
I wonder if this is related to the astronomical concepts of redshift and blueshift, where the light spectrum of things like galaxies moving away from us look redshifted, since the light waves are being ‘stretched’, and the opposite for bodies moving closer to us.
No, it has nothing to do with relativistic red/blue shift, except that they are both related to the fact that red light has a longer wavelength than blue light. Chromostereopsis is caused by chromatic aberration in the eye, where the lens focusses red and blue light at different points.
Well, at some point someone did change the diameter of the inner cardboard tubes, because I have right here a pair of toilet paper tubes, one fitting easily inside of the other (the newer one is the smaller one).
I am seriously disappointed in you people. Are you not Dopers? 53 posts into a thread about optical illusions and no penis joke? “It always appears to be bigger than …”
Oooh, racy! (Sorry, I have PTSD from paper towel tube threads…)
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Our bathroom floor tiles do that, too. It comes under the category, for me, of “I don’t need drugs, I can just stare at this…”
I only dated girls with small hands for that reason.
I just remembered another optical illusion that’s fooled me several times.
We’re letting our son, Sonlost II, who’s a high school senior, park in the garage to make it easier for him to get to school in the mornings, not having to get in a freezing car covered in ice and snow. I, being WFM since the pandemic started and therefore don’t get out much, am relegated to park outside.
Since he was having a bit of trouble parking in the tight space, Mrs. Solost rigged a string and weight thing, like some people do with a tennis ball so you know to stop when it touches the windshield. Only Mrs. Solost used a troll doll instead of a tennis ball.
It has a big mess of dark brown hair like an actual mammal would have, not neon red or blue like other troll dolls. When Sonlost II’s car is not in the garage and I’m walking through there, the troll doll hanging from the string looks, from the corner of my eye, like it’s moving relative to the background, creating a very convincing illusion that some small critter is scampering in the garage.