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Optical Illusions of the Year (kottke.org)
92 points by Tomte on Sept 6, 2022 | hide | past | favorite | 48 comments


My favourite optical illusion from 2021 was Find The Curved line https://www.reddit.com/r/opticalillusions/comments/rc78kw/ar...

"It was made with rotated repeating tiles as a total and complete accident. I was making a gaming map!"


That's fantastic, and much more interesting than the changing room to me. It's similar to many older illusions, but the last image that shows why it happens is a new aspect.



I don't get the changing room illusion. I saw things slowly disappearing over time. I thought the big reveal was gonna be that they aren't actually disappearing (ie an illusion), but nope - they are indeed slowly fading out. What's special?


First time for me that swirly thing was distracting my attention and I was doing rapid saccades looking for weird hidden items (even though I knew that was probably part of the illusion, seemed best to play along). I didn’t notice a single thing changing so the illusion worked perfectly for me. Second time watching it was easy to see the changes.


Apparently many people didn't notice anything disappearing, because they shifted their eyes around the video. I also noticed things changing, but if you'd stopped the video before the big reveal and asked me to list them, I would have listed only a small fraction of what actually changed: the bottles on the top left, the patio door curtain, the pillows on the couch. I missed the majority of changes, as did--I suspect--everyone.


I saw nothing change. So apparently you looked at it the wrong way!


There aren't any instructions in the video (other than "See if you can spot the difference"). Was I supposed to focus only on the spiral disc or something?


I think the idea is that by trying to actively look for changes, you shift your focus around, but don't actually remember that well what is placed where.

At least for me, my focus kept wondering around the room, never noticing that things that was previously there was replaced by something else.


They were trying to nudge you to rapidly scan over the whole room with quick eye movements, like one of those hidden item puzzles. If they explained what they wanted you to do in too much detail then you probably would have suspected the trick.


It doesn't even say that - it asks you to look for items that are "out of place". When I first watched it I immediately paused the video to have a look. Not the best instructions!


Yea - same with me! Immediately paused to make sure I had the time to examine a little more closely. Ooops.


No, I was just kidding.


Yes, maybe I misunderstood the instructions but I was looking at the bottle of champagne trying to work out if it was "out of place" for the room that I noticed it was fading out. I had also noticed weird flickers earlier that I couldn't place which were presumably other items fading in or out.


Same, I noticed the lights on the tree but that was about it directly.


The big reveal was that most things changed. I only noticed the photos fading out the first time around.


SPOILER: Like you and others, I noticed that some objects were changing, very slowly. What I didn't realize, until the video pointed it out later on, is that nearly every object placed in the room was changed. The "before" and "after" pictures were shocking to me: They look like two different rooms. Evidently I cannot notice and keep track of more than a handful of things changing simultaneously in an image.


I was looking at the clothes lying on the back of the sofa when it started, and it was painfully obvious it was slowly fading.


Way more changed than I thought. I was only focused on the ceiling panels and the curtain.


Optical illusions are adversarial samples engineered to trick the biological neural networks making up our visual system to perceive things that in reality are not there.

Like the OP, I found the "changing room illusion" very powerful, because it showed me how shockingly unreliable my own visual system can be! Magicians do this to us on a regular basis.

Luckily for all of us, no one appears to be using these kinds of adversarial samples to fool us in dangerous situations, e.g., when we're driving vehicles on a fast highway.


Technically our visual system making things up is the norm. It has to do a lot of predicting using a known distribution, because our eyes are fairly economical in their design. People always say how come evolution could make the human body so perfect, but that's the illusion, many of our limitations are hidden from us.

If we would have a better understanding of our limitations we wouldn't lose 1.3 million people each year to road traffic deaths.


The linked one with the rings didn't work on me. I had to focus to see what they said I should be seeing.


Same. Could it be that maybe seeing 'impossible' shapes colliding and passing through each other is common these days, so the brain won't automatically register as "bouncing back an forth"?


I saw it.intellecruallyi knew they were the same, but some were spinning and the others ocillating


Same here.


I see some comments here saying they saw things change, so I guess not only is the judging here highly subjective but also objectively some illusions will apply more to some people than to others.

Personally, I absolutely agree with the OP that the 2nd place was most impressive here - the checkerboard "invisibility cloak" is convincing but not novel. The reveal was easy to predict. The changing room I was still amazed at after rewatching numerous times - I could start to notice a small number of things changing each time, but the overall scale of the change is still hard to believe.


I'm not impressed by the changing-room 'illusion' since I clearly noticed most of the changes on the first watching without knowing I wasn't supposed to. Part of the reason may be the somewhat clumsily compressed video which shows clear jumps in scenery between key frames as these draw attention to the parts of the scene which are changing. Maybe this works better with a longer key frame interval (which avoids the jumps but lowers image quality) or a really short one (which also avoids jumps but radically increases file size).


I don't understand how the Crocks and Socks is an illusion. If you take a screenshot of both shoes, one is gray while the other one is pink. That's not an illusion at all.


The threshold of perceptible change, a fascinating concept. Try as I might, I never manage to observe the progress of twilight while concentrating on the sky. Yet glancing out the window one minute, then the very next, the difference in brightness and hue is unmistakable.

Imagine reading a book in an artificially lit, climate-controlled room. If, over the course of hours, the lights gradually dim and the temperature rises, or the background noise increases, at some point you would become acutely aware of your discomfort. But you wouldn't be able to say how or when it came to be, or even if the situation had always been somewhat like this. What if the hue of the lights varied cyclically over the days of each month? Would you ever notice? There's fractal applicability to this, scaling so far as to the flux of culture of a civilization over many years.

https://www.google.com/search?kgmid=/m/02txfg



Spoiler...

It's very carefully calibrated. At 2x speed you see things change; at 0.5x you see them in transition.


Not only is the timing calibrated, but also I think the setting (& a lot of the changes).

The curtain change seems significant except that it's against a reflective window with items visible behind in darkness - that lends itself to vague/semi-transparent objects being "acceptable" to the eye within that space. The blue & yellow picture and rug are also blurry/vague patterns which lend themselves to fading in/out. The ceiling is dirty off-white, lending itself to tiles being off-colour at times. The books on the shelves the same. The only very "finite" objects in the scene (and by far the easiest to notice changing) are the wine bottles.


I wonder if size is also an issue.

I watched it full screen at 34". I saw changes ghosting in where I was looking e.g. bottles appearing over the top of books.

I couldn't pay attention to the whole scene because there is just so much clutter so I didn't notice the curtain moving and such but I could tell other objects were greying in my peripheral vision though. I can't really call the experience as an illusion, just an example of how narrow my attention is of a complex scene.

Maybe if I wasn't looking at something so big, I wouldn't be concentrating on such small subsections of the scene.


Obviously everyone has their own favorite optical illusion depending on how convincing it was for themselves. My favorite still is the checkerboard illusion https://en.m.wikipedia.org/wiki/Checker_shadow_illusion

A few times I've shown it to people and the response was "I don't get it. What's the same?" Because they can't believe that their initial reading of the description is correct!


Mine is the "Peripheral Vision Distorts Faces into Grotesque Masks" one.




> > https://youtu.be/jb29X2SrgDM

> Expected Kokichi Sugihara to be represented as always, not disappointed. I will have to try and replicate this one as well.

I really don't see this one


It's subtle, but the mirror images are often "wrong". Like at 0:12 the yellow shape is laying on its side, but in the mirror it's standing on one of the short ends. At 0:28 the rightmost woodcube is laying on the bark, but in the mirror the side down is the chopped side.


Well, yes, but my brain immediately went "it's a piece of paper" and I tried to figure out what the illusion was.


(Too late to edit but I hope this doesn't come across as more condescending than I meant. I really thought there was more to this that I couldn't see.)


Yeah, I think the "ambiguous cylinders" are more impressive. I've implemented some of his figures and made available for download here: https://github.com/Matsemann/impossible-objects

What's cool about these is that they're tangible. And for some of the shapes, it works well even when looked at with two eyes (which supposedly should tell your brain the trick) and from not the perfect angle.


Wow, yeah, those are much more impressive. (Your 3D prints deserve mounting on a turntable or something.)


Why on earth are we going to kotke.org instead of the actual site?

http://illusionoftheyear.com/


http://illusionoftheyear.com/ is unresponsive for me.



This is something similar to how Ebay changed their logo color. I think it was here on HN couple of days back: instead of a drastic change in background color slowly changing by one gradient kept it unnoticeable.


Bummer -- I thought kottke was back!




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