We were discussing this at home today (we went down to my parents' to celebrate my father's birthday), and my father (who has not, as far as I know, seen the image) enquired, fairly seriously, whether skaters in the Northern hemisphere spun the opposite way to those in the Southern hemisphere, like water running out of the bath the other way (allegedly)! I don't think so, but it's a nice idea!

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Mrs Redboots
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Ice dancers have lovely big curves!

hahahaha! True! Actually, for a really long time (many years) I thought that water running down toilets etc spiraled in different direction for northern and southern hemisphere....related to coriolis effect etc. But interestingly, it turns out that the forces are so weak that it doesn't really cause water to flush down sinks and drains in the same direction (in one earth hemisphere). I found out that the direction of the spiral just depends mainly on factors like geometry of the flushing system...like pipes and how the water runs down to go into the pipes....which of course also depends on geometry of the system. So basically, in one hemisphere, water can spiral either direction.......depending on the system geometry.

For those that are really having a hard time trying to get the girl to spin in the 'other' direction.....

what you can do is to get a pen or a pencil, and dangle the pencil downwards right in front of the girl spinning on the screen. And then make the axis of the pencil or pen rotate in the direction that you want ....eg clockwise ....then just focus your eyes on the dangling pencil as you're rotating the pencil in a clockwise direction ..... eventually, you will notice that the girl will rotate in the same direction as the rotating pencil. Or, at the very least, you will see that the girl will rotate slightly in the other direction. But I think you'll be able to get the girl rotating in the opposite direction using this method. It will work for you. Just remember that as you're rotating the pencil, try to keep the pencil vertical all the time. So the axis of the pencil will just go around in a circular path while the pencil remains vertical....and you just focus your eyes on the pencil.

Definitely clockwise....but I'm sure I'm not right-brained lol!

S xxx

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Seeing the two images sides by side freaked my brain even more!

At first they were going opposite directions, then I focussed on one to change her, so for a while they were going the same way, then the other one flipped to make them opposite again.

Cool, weird, absorbing, and somehow annoying at the same time.

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Karen

I skate - therefore I am

Ok, I think i'm going out of my mind... For the original, I can only see it going clockwise... seriously, I cannot make it go anticlockwise at all!

Then when I first saw the two images, I thought the left (original) was going clockwise and the right was going anticlockwise. After reading the rest of hte posts, I now cannot make either of them go anticlockwise at all!!

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But you have a degree in art!

I can convince it to change direction by looking at the shadow under her foot and telling myself that it's either in front or behind her. This has had the disturbing side-effect that instead of spinning, she now wobbles from side to side inelegantly

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Pretty sure that you can manually get your brain to see the picture spinning in the direction that you want. Just get your finger and hold it upright (vertically) in front of the picture....and keep it upright all the time. Then make your finger go away from you and towards you in a circular pattern.....eg make it rotate in a anti-clockwise direction. Then focus your eyes on your finger as the axis of your finger is going around and around in a anti-clockwise direction. And you will also see the picture in the background too...but focus mainly only your finger as it moves around in a circular path (keeping you finger vertical all the time).

Eventually you will see spinning of the dancer do a flip in the other direction....and if you keep using this method for long enough, you'll even be able to see the dancer continue to spin in the counter clockwise direction.

The other thing is, I don't think that this illusion has anything to do with left or right half of the brain. It is just a illusion that takes advantage of the brain having a tendency to fill in missing information ..... like fudging visual information...or compensating for lack of visual information.

Well the arm is bent, so technically it wouldn't have to change the position by much, but it's difficult to draw that way. However, for the direction you do see it go in, the arm also has to change positon, except in the first 12 frames somewhere instead of frame 24 and onward.
That's why I'm saying it's impossible to spin this way. She has too much wobble and too much change of arm position (at least once per revolution) to spin on ice.


The flipped animation is spooky, technically, if you'd be REALLY one brainsided, you'd have to see them both going cw or ccw, since both animations can be seen in cw and ccw... So why the brain sees them as spinning in opposite direction is a curious thing all together.

They flipped for me when I stared at the center line where the two pictures touch. First the left one started going CCW, then they both did. Weird!

That's because the news report is probably inaccurate or they're lying hehe. I don't think it has anything to do with which hemisphere of the brain is preferred. It is probably just due to a usual preference our processing has in interpreting this type of display.

hehe! yeah! That really flipped too when I focused mostly on the center line, after trying that out with your method. When focusing on there, the brain processing can get a bit fuzzy on which way to interpret this illusion of spinning, and can change its way of interpreting the spin directions hehe...very weird.

Also, with black's "double image", my twirling-the-axis-of-a-finger-in-front-of-the-spinning-picture method doesn't work so well......possibly because of light/dark shades from the second picture interfering with the first picture. My twirl the finger method works really well when there is a single picture by itself. For black's double picture, I covered 1 of the two dancers completely with one hand, and the finger twirling method doesn't work well at all. The shading at the edges of the covered dancer might be interfering with the illusion of the uncovered dancer.

Ditto.
I cannot see any other way, for the life of me.
She is on her L foot, inside edge, doing a back spin. Clockwise.

The text of Right Brain applies to me, for the most part.

Thanks for sharing this with us!! Fun.

She only spins clockwise for me. I am left handed and I spin clockwise on the ice.

I have some right brain aspects but not all. I'm not a true lefty (I play racket sports with my right hand and use scissors with my right hand - go figure!)

I cannot get her to spin anti-clockwise at all.

YAY, I got the right picture to go anti-clockwise. But goodness, that took quite some effort, and if I blink again, they both go back to clockwise.

I'm starting to think that too, but it is a really fascinating illusion nonetheless!

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hehehe....nice work! It's great that you could see opposite rotation like that. Yeah..... the latest trick I use now is to point the index finger downwards (toward the ground)...just in front of the spinning picture (the single spinning picture...not the double one that black posted). And then I just make the index finger do a precession in the direction that I want.... and have the eyes focus on the precession of the finger (eg anticlockwise). And eventually, the spinning dancer will go the same way as the precessing index finger. But looks like you know how to get the rotation now already, so that's really great!

I agree... one of the best and amazing illusions I've seen. The chess-board illusion with the same coloured gray squares caught me by surprise too.

She keeps going clockwise for me...
edit: with the mirrored ones, I saw clockwise on the left side, and anti on the right, i scrolled down the page, scrolled up and then boom they were both going clockwise, then i scrolled down and up and it was clockwise on left and anti on the right again. This is fun

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Tidesong

With the mirrored ones, I had similar experience to Tidesong.
Left one (original) goes clockwise.
Right one (reversed sequence of gif frames) goes anti-clockwise.
Whereas, for a "rightbrained" person, you might expect them both to go clockwise.
So perhaps there is something with the angle of the body? or shading? that makes one direction slightly preferential?

Occasionally, spontaneously, the left one changes to anti-clockwise for a minute or two, then reverts. But the right one always stays anti-clockwise.

I'd love to see a really technical explanation from whoever created the illusion!!

I just put a mirror up to my computer screen and watched the original ("clockwise") image in the mirror. It went anticlockwise. I then looked back at the original image - it went anticlockwise for a couple of revolutions, then reverted to clockwise ...

Also, my brain seems to be learning something-or-other from watching both directions, as it is now flicking directions more frequently.

Am getting giddy, better stop!

i see her going CW. i have absolutely NO idea HOW you could see it going CCW! I'm trying SO hard and i can't see it any other way, even looking at it out of the corner of my eye and stuff

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ahh I got it to spin the other way! yay! i had to blur my eyes and try to make the blurred figure go the other way, then i got it.

oh and btw, i spin CCW. and i seem to be VERY right brained...

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this is nuts!!!!!!!!
if I weren't asked, it wouldn't have ever occurred to me that she might be spinning CCW! everything says CW no matter how I look! but then, as I read the text to the left (not focusing on her) I see CCW, and as soon as I look at her, she's CW again. I did this lots of times and could never keep the CCW as soon as I look at her!

OMG i GOT IT I GOT IT~!!!!!!!!!!!!!!!!!!!
I got to look at her and see CCW!!!
ok here's the solution (as if it were a problem to begin with!):

CW: when she's facing you, she's swinging her foot lower, closer to the ground, and then up when she's away from you.

CCW: she swings her foot higher when facing you and almost touching the ground with away from you.

the height difference between the facing you and facing away seems more dramatic going CCW.

now I can see both ways at will yay!!!