It’s just the picture changing direction every 40 rotations or so (can’t be bothered to do an exact count). The nature of the picture makes the direction change look fairly seamless.
Not so. I can change it at will.
(TM probably whooshed me, but thought I’d clarify since it’s GQ.)
When she’s rotating counter clockwise her left leg is extended and is moving into the screen on the right while her back is rotating into view.
It’s not just an image switching rotations every so many frames since I can make it flip back and forth every frame so that the extended leg just sweeps back and forth in front of her or switch it on demand and let it keep rotating in whichever direction I prefer.
I, too, can change her direction by looking away and back.
And she’s got great nips.
Yeah, she goes both ways (and I’m good with that). The first time I looked she was counter-clockwise, but switched within seconds to clockwise. I have trouble instigating a change in spin direction while looking directly at the image, but looking away or switching briefly to another tab will do the trick (though not always). I thought at first that my predominate perception of spin direction seemed to be clockwise – by about 2:1 – but that seems to be evening out as I switch back and forth between tabs while writing this. Perhaps familiarity with the image allows greater ease in switching between versions?
Oh, and jjimm is right, she does have nips.
There are two pictures. One with the right leg lifted and one with the left leg lifted. They seem to switch between after about 30 to 50 revolutions.
Try this, watch the lady’s legs near the hips, each time she rotates call out if it is the right or left leg that is in the air. After a bit, you will see it is the other leg that is lifted.
I can force myself to see the image rotate in the “wrong” direction if I do like tbdi suggested and watch the legs first.
ETA: you guys are right, great tits.
That’s weird–the shadow forces me to see it counter-clockwise! I can only see it clockwise when I ignore the shadow.
-FrL-
She’s going clockwise, and I want to marry her.
EDIT:
I jumped between tabs, and she was going counter-clockwise at first, but when I looked away she was back to clockwise.
That tells me that she’s too fickle for marriage. I’d still like to spend a weekend with her.
It took me a while to be able to see counter-clockwise (CCW) rotation. What worked for me was the following:
(1) Close your eyes and imagine seeing the dancer rotating CCW for awhile.
(2) Look far off to the side of the image, so that the dancer is just barely in your peripheral vision. If you’ve prepped yourself long enough to anticipate CCW rotation, you might be able to see it now.
(3) Slowly, slowly move your eyes towards the image, all the while affirming to yourself how CCW the rotation looks.
(4) Finally, look at the image square on.
I can’t make her go anyway but clockwise. I’ve worked so hard to reverse her that I’m almost willing to believe that the people who claim to see her go anti-clockwise are conspiring to whooosh me. Almost.
FWIW, I’ve always considered myself pretty strongly left-brained.
Do it in a room with about five or six other people. Chances are some will see it going obviously one direction and others will see it going obviously the other direction at the same time. The animation doesn’t change at all.
I could make her switch by either flipping my head 90 degrees or by covering up everything but her feet and consciously imagining the spin in the other direction.
:eek: Holy S***!
That worked for me. I could only see her rotating clockwise. Followed your instructions and it worked. Of course, once I started analyzing why I was seeing counter…pow!..back to clockwise. 
This is a great animation. Thanks for posting it. It seems to me there would have to be some other corrobarative research to see if it separates out right- and left-brained-edness (sp? word, even?) b/c if that function sits on one side or the other, whichever way you perceive the illusion, it’s still processing on a single side. If the CW-v-CCW spinning perception function sits on both sides of the brain (doesn’t seem likely) then perhaps it is a test of which side is dominant for that particular perception.
I think it is a great oversimplification to think of the brain as having a dominant side. Sure, certain functions reside on both sides, or at least require bilateral processing, and some functions are fairly unilateral. But it doesn’t seem correct to me to draw an inference that because a particular lateralized function is well-developed in a given individual their overall brain function has a hemispheric “dominance.”
It is 100% counter-clockwise for me and I can’t see it any other way. I have to ask, I am imagining the girl dancing on my wrist watch, is that the right way to judge clockwise or other?
With a little practice it’s not too hard to make her spin either way, just like you can learn to point down a left or right eye line once you know what’s being tested for.
Perhaps one way to decide if CW and CCW perceptions reflect processing on opposite sides of the brain would be to do a PET scan while someone is looking at the image and see if only one side lights up when she is going in a specific direction.
Then you have the tester make her go in the other direction and see if the other side of the brain lights up, and then you do more than one tester to see if the perceived direction correlates with one side or the other.
And you won’t be able to use the seedy crowd posting here as testers, because for most of us the part that’s lighting up is the small peripheral brain that controls most functions in males (about 3 feet south of the main one). But I digress.
She’s going counter-clockwise for me now.
This is really a cool animation.
One thing I found is that viewed in Internet Explorer she spins considerably faster than she does when viewed in FireFox and the faster she goes the harder it is for me to switch direction.
If different sides of the brain tended to see different spin direction wouldn’t covering one eye or the other make it easier to do? I don’t find any difference in which direction is preferred or how easy it is to make the switch.
I can make it switch back and forth by focusing on the extended arm as it sweeps behind / in front of the dancer. If I do it every time, it looks like she’s constantly twisting around like some kind of shapeshifter and sweeping back and forth like pendulum.
That’s how I’ve been understanding it.
I can switch back and forth now, but I still can’t do it while looking directly at the image. I either have to look off to the side or cover the entire image except for the foot.
Also, the image looks a little unnatural when the dancer is turning CCW. The main problem seems to be that she is tilted at a slightly unnatural angle. When she is turning CW, it is as though I am watching her from a position at the same height as her head. When she is spinning CCW, though, it is as though I were watching from a lower position, and she is tilted back so that I can see the bottom of the foot of her vertical leg when it swings by (or I could if she weren’t in shadow).
If I shift focus to look past her so that I get two images they are presumably each being processed by a different eye but they stay synchronized. They also tend to swap back and forth much more often than when focused on the single image.
I also see what Tyrrell McAllister does; she’s tilted very slightly back when spinning CCW.