The Perpetual Diamond
June 3, 2019 7:40 AM   Subscribe

The perpetual diamond is an optical illusion that produces motion continuously and unambiguously in one direction despite the diamond itself never physically changing location. Link is to online paper; scroll down for brainbending video demos [flashing lights, only if you click play].
posted by carter (49 comments total) 36 users marked this as a favorite
 
Really cool, but, ummm, feeling a bit queasy right now
posted by NoMich at 8:17 AM on June 3 [3 favorites]


This really fucks my stupid brain's shit right the hell up.
posted by entropone at 8:35 AM on June 3 [5 favorites]


That was pretty fucking trippy...
posted by TedW at 8:43 AM on June 3


Combining the flashing effect with stereographic images has led to some really interesting gifs that seem to be perpetually in motion as well.
posted by adzm at 8:46 AM on June 3


The effect was so strong that I didn't immediately notice that the diamond isn't moving. I scrolled away to read the text while waiting for it to get to wherever it was going, and only realised when I came back that it hadn't gotten anywhere.
posted by Eleven at 8:51 AM on June 3 [3 favorites]


I was kinda hoping they'd do a version in the second video where they set the isolated borders to different directions. I'm glad they did the growing and shrinking, but would it be possible to make it seem as tho one side was shrinking while the others were expanding or moving outward? Can you make the diamond seem to squash along one axis while expanding on the other? Or does the illusion break down when adjacent boarders don't reinforce each other?
posted by es_de_bah at 9:07 AM on June 3 [2 favorites]


The fun thing about these illusions is how they reveal so much about how your optical system and brain processes vision. This short article doesn't speculate on exactly why the brain interprets this stimulus as motion; any guesses? It seems related to shadows.
posted by Nelson at 9:08 AM on June 3 [2 favorites]


I understand reasonably well what is happening here and it still feels super trippy.
posted by biogeo at 9:09 AM on June 3


Even better: set both videos going at once so the sound overlaps.
posted by The corpse in the library at 9:20 AM on June 3


es_de_bah, that's a good question. I don't know for sure but I expect you could manipulate the diamond as you suggest, making it squash/expand.

Nelson, it has to do with the way individual neurons in the visual system encode features of the visual scene. Without getting too detailed, your early visual system has a lot of neurons that are tuned to respond to edges, where there's an abrupt change in luminance. The greater the contrast of an edge (the larger bright-to-dark difference across it), the higher the firing rate of the neuron. I'm not 100% certain the exact mechanism at play here, but I suspect it has to do with the fact that higher contrast means the neurons can respond more rapidly, effectively creating a very slight time delay in processing between the diamond-to-border edge and the border-to-background edge. By manipulating the phase relationship between the border and the background's changing luminance, you create a situation where there's a constant delay between the activity of neurons processing the inner and outer edges. Farther along the visual processing stream, there are neurons that are highly sensitive to these kinds of delays and use them to process motion. This input produces constant drive to the motion-sensitive neurons, producing a constant perception of motion even though nothing is moving.

I don't think this is everything that's going on; there's probably an involvement of global processing versus local processing, and if my description were accurate you should be able to get the same phenomenon by changing the luminance of the diamond and borders while leaving the background fixed. making you bored for science or another visual neuroscientist could probably provide a better explanation.
posted by biogeo at 9:27 AM on June 3 [10 favorites]


That diamond is white and gold.
posted by delfin at 9:29 AM on June 3 [8 favorites]


damn, looking at that for even a couple of seconds makes my head hurt. I feel like most optical illusions don't have that effect on me; maybe it's the slow strobing-light effect getting to me moreso than the moving-but-not-really effect.

very cool though; optical illusions are such a consistently fascinating layman-friendly demonstration of the imperfections and quirks of sensory perception.
posted by Kybard at 9:31 AM on June 3


This is really cool and I'm glad I looked at it, but yeah, even a couple of seconds was enough to make me queasy and make my eyes hurt. So weird.
posted by fiercecupcake at 9:38 AM on June 3 [1 favorite]


Yeah, I love optical illusions, brain hacking, novel experiences and being totally disoriented.

But when the 2nd demo video got to the growing/shrinking/moving part I actually said "OW OH FUCK" and had to stop watching.

So at some point someone is going to invent an actual visual-cortex metavirus like the one in Snow Crash, right?

Because some of these more advanced optical illusions feel like they're getting to the point they could reliably trigger seizures or migraines or something.
posted by loquacious at 9:38 AM on June 3 [2 favorites]


Weird, I cant get to it because:

Your IP (n.n.n.n) is blocked.
Block Reason: This IP was identified as infiltrated and is being used by sci-hub as a proxy.


That's from my phone....
posted by edheil at 9:42 AM on June 3


The web call is coming from inside the phone!
posted by cortex at 9:44 AM on June 3 [2 favorites]


But, yeah, this is a real good one. I’m always excited by this kind of optical fuckery and especially when it can be accomplished in such a spartan way; in another life I think I would have liked to professionally explore the weird artifacts and edge cases in our vision processing.
posted by cortex at 9:48 AM on June 3


[opticalfuckery tag added]
posted by carter at 9:52 AM on June 3 [1 favorite]


is this what the food delivery companies use to make it look like the courier icon is moving when it demonstrably is not or is that pure projection on my part
posted by wreckingball at 9:55 AM on June 3 [5 favorites]


Turns out it's mostly weird artifacts and edge cases.
posted by biogeo at 10:01 AM on June 3 [2 favorites]


I stopped looking at it because it felt sort of seizure-y, and I’d rather not.
posted by GenjiandProust at 10:02 AM on June 3


I actually don't have a whole lot to add to biogeo's ideas - motion perception is kind of its own little corner of vision science, and I'm not an expert on it.
posted by Making You Bored For Science at 10:59 AM on June 3 [1 favorite]


Barfy in the best way!!!
posted by helmutdog at 11:29 AM on June 3


after a few seconds, I wanted to see if I could break the illusion of movement, and figured the best way would be to place my finger at one of the corners to anchor the diamond and show my brain that it obviously wasn't moving. It didn't seem to move any less, but started to make my head hurt more. Then I tried a finger on the top and bottom corners, figuring that if there was obviously no room for it to move up and down, my brain would reflect that. Again no luck, but the diamond did start shaking left and right too, and so I decided I better quit while I was still relatively sane.
posted by skewed at 12:14 PM on June 3 [4 favorites]


The origin GIF of the Psychonauts
posted by Morpeth at 12:29 PM on June 3 [1 favorite]


I found that if I put my thumb right in front of the forward tip of the diamond, as if it would block the diamond from moving in that direction, the illusion vanished and all I saw was that the borders and the background were flashing.

... But only if the video is full screen and I'm close to the monitor. If I try it with the video at the little embedded size, then I keep seeing motion no matter where I put my fingers.
posted by straight at 12:30 PM on June 3


If I make the mistake of watching YouTube basketball clips late at night, I often can't go to sleep because when I close my eyes I do see blackness, but the motions of the basketball game are somehow projected into the blackness without perception of light or any shape or image, for up to half an hour.

So I expected to see similar motion from this when I closed my eyes, but no.
posted by jamjam at 1:16 PM on June 3 [1 favorite]


Metafilter: mostly weird artifacts and edge cases
posted by treepour at 1:24 PM on June 3 [5 favorites]


If I make the mistake of watching YouTube basketball clips late at night, I often can't go to sleep because when I close my eyes I do see blackness, but the motions of the basketball game are somehow projected into the blackness without perception of light or any shape or image, for up to half an hour.

Oh man, Guitar Hero used to eff-me up for this. I'd play a couple of songs and then I'd look away and there would be a channel up the middle of my vision where, like, the middle of my couch would be moving in a different direction from the two arms, but my couch wouldn't actually be moving at all. It was very, very trippy.
posted by jacquilynne at 1:37 PM on June 3 [6 favorites]


This seems to be a variation on the technique used for the rotating snakes illusion (the source site, with tons of illusions plus academic papers).
posted by D.C. at 1:50 PM on June 3 [3 favorites]


If you were an insect – say a butterfly – and you could generate an effect like this by flapping your wings, I wonder whether you could make a predator miss sometimes.
posted by jamjam at 1:58 PM on June 3 [2 favorites]


@agshapiro2 on twitter linked to an interactive demo.
posted by tayknight at 2:37 PM on June 3 [5 favorites]


So at some point someone is going to invent an actual visual-cortex metavirus like the one in Snow Crash, right?

Probably not, just because if such visual "basilisks" were possible, nature would have already discovered and exploited them: insects with visual patterns that crash predators' brains, cuttlefish that crash their prey's brains with flashing body colors, plants with deadly leaf patterns, that sort of thing.
posted by Pyry at 3:19 PM on June 3 [3 favorites]


Of course it's also possible that the reason such attacks don't seem to be possible against natural neural systems is specifically because they've evolved to be robust against them: perhaps we've evolved in an environment of low-level computational warfare and full-blown basilisks have never emerged because defenses have evolved in tandem.
posted by Pyry at 3:41 PM on June 3 [3 favorites]


That tickled my visual processing area like an oncoming migraine. I had to stop looking at it and felt funny for a few minutes afterwards. I tried putting my mouse pointer on the edge of the shape to prove it wasn't moving, but my brain didn't care.
posted by w0mbat at 3:44 PM on June 3


My brain is telling me that it's a view of an illuminated tunnel and the passing lights are rim-lighting the foreground diamond.

I'd love to try it in some animation but I'm wondering if it would pass a Harding test

It might be a good idea to put a "flashing lights” warning for people with epilepsy or migraines.
posted by bonobothegreat at 3:45 PM on June 3 [1 favorite]


(Post title is misspelled)
posted by oneironaut at 3:45 PM on June 3


Combining the flashing effect with stereographic images has led to some really interesting gifs that seem to be perpetually in motion as well.

what so like, a dick that's always getting harder?
posted by 5_13_23_42_69_666 at 4:40 PM on June 3 [1 favorite]


So at some point someone is going to invent an actual visual-cortex metavirus like the one in Snow Crash, right?

Well, there was that 1997 Pokemon episode that sent almost 700 Jaoanese kids to the hospital, some with seizures, and affected GOK how many more . . . and which also seems to have resulted in the unlamented death of Pokemon 'Porygon', who has never been seen again.
posted by jamjam at 5:35 PM on June 3 [2 favorites]


[Fixed typo and added flash warning]
posted by LobsterMitten (staff) at 5:52 PM on June 3 [1 favorite]


if such visual "basilisks" were possible, nature would have already discovered and exploited them: insects with visual patterns that crash predators' brains, cuttlefish that crash their prey's brains with flashing body colors, plants with deadly leaf patterns, that sort of thing.

Well maybe they are only possible in a certain sort of brain with a certain level of complexity. If there were basilisks that could only crash something like the language center of a human brain it's quite plausible evolution wouldn't have found them yet.
posted by straight at 5:53 PM on June 3


And if we're talking "actual visual-cortex metavirus", I feel compelled to ask what you've got against our 5500 year old pal, written language?

I mean it has mutated a bunch of times and killed millions of people as it spread all over the world — and no one has ever found a cure for it — but some people will claim it isn't completely evil.
posted by jamjam at 6:03 PM on June 3 [5 favorites]


Today I learned that jamjam is William S. Burroughs.
posted by Don.Kinsayder at 8:05 PM on June 3 [4 favorites]


only possible in a certain sort of brain with a certain level of complexity

see also: the "crucifix glitch" (PDF of Blindsight endnotes, Peter Watts)
posted by Two unicycles and some duct tape at 8:52 PM on June 3 [2 favorites]


Has there been any progress done with visual illusions in stereoscopic vision recently? Now that VR equipment is getting cheaper and more easily accessible, it'd be really interesting to see exploration of animated gradients and such in a 3d space.
(i googled a bit but couldn't really find anything)
posted by Dee Grim at 12:21 AM on June 4


For me it seems to move continuously a bit and then jump back and start over at a regular rate, about every 3 flashes or so.

It's also completely headache inducing.
posted by bongo_x at 12:48 AM on June 4


C'mon, didn't any of you kids do LSD? Doesn't this all look just a little too familiar?

Kidding aside, that is a fascinating article - thanks!
posted by From Bklyn at 12:49 AM on June 4


Using that interactive demo with the background turned off, I see the diamond as if it's shifting back and forth by a single pixel, even hiding half of the diamond with my hand - nothing but two diagonal lines cycling between black and white. There's a certain range of zoom that it works within, but it works so effectively I'm amazed something so simple wasn't stumbled upon sooner.
posted by lucidium at 4:43 PM on June 5


Same effect with Mickey Mouse instead of a simple diamond shape.
posted by Nelson at 7:33 AM on June 18 [1 favorite]


« Older At this point, I have to turn off the tape...   |   Did well playing an unfair game Newer »


This thread has been archived and is closed to new comments