At some point when her legs appear together (because she’s facing you or turned away) they switch the leg that is extended and reverse the direction.  It seems like a continuous spin because of the motionand similar general shape at that point in the animation, but there exists a concrete transition.  She moves clockwise when her right leg is extended and counter clockwise when her left leg is extended.  The direction is unmistakable due to her distinct three dimensional nature.  Watch it long enough and you’ll see the transition.  It seems like an optical illusion, but really it just catches you off guard.  I wonder what kind of brain you have to have to realize she’s going both directions at different times and that Mr. Harlow’s entry and Perth Now’s article is crap?

How bizarre.  I can only see her as turning clockwise, no matter how hard I try.  I understand that her dance is symmetrical and not chiral, and that all three-dimensional clues are imposed after I “decide” that she’s moving clockwise, yet I can’t see her differently.

And no, theocrat, I must beg to differ: the dancer is not “turning” in either direction, or alternating directions, but is rather a symmetrical series of flat images.  It might well be that interpreting how we see it as an indication of whether we are “left-brained” or “right-brained” is crap, but the illusion is real.

I can only see her going clockwise too.

I saw her changing direction as well. And besides, it’s impossible to interpret her moving in two different ways. When it looks she’s going clockwise then she is going clockwise.

From the link:
[M]ost people will see this dancer moving counter-clockwise because they use more of the left side of their brain and tend to be more logical and practical. People who see the dancer moving clockwise (like me) are right brain dominant and tend to be more risk taking and imaginative.’

That surely is rubbish. Why would the dominance of one brain half over the other have anything to do with it? Also, I’m one of the most rational persons I know and I cannot see the dancer spinning any other way than clockwise.

In any case, I think that she is spinning clockwise. There’s one visual clue that in particular catches my eye: the outstretched arm. The arm is higher when behind her, at the level of her hip, and comes downwards to the level of her butt when in the front, consistent with clockwise rotation as viewed from this perspective.

Cant see her turning any way but clockwise (and while I am flattered by the creative tag, many of the adjectives listed don’t really apply to me).

And theocrat, don’t let good old scepticism make you too suspicious. Ceci n’est pas une pipe! This is an optical illusion, and the scientific question is: Does it APPEAR a certain way to you or not? The tricks of how its done do not invalidate the experiment.

I’m with Theocrat (Zilch’s comments taken on board).  My wife claims she switches direction, as does her son. He is Dyspraxic ("spatial dyslexia"). My son (dyspraxic, dyslexic and some mild symptoms of asbergers) only sees clockwise. 

The biggest clue is the pointing of the foot.

If you want something that really throws your brain you need to go to the airship hangers at Cardington in Bedfordshire, about 30 miles north of London.  Located on flat terrain, with just a low rise of hills on the horizon, you look at them and go “so what?”.  The best way is to round a corner so you see them from about a mile away without expecting it.  Then your eyes pick up a few clues, such as the house in front.  There is a moment of visual confusion as your brain tries to hold two images simultaneously- hangers ‘close up’, while it struggles with the realisation they are REALLY BIG hangers a long way away. Incidentally in the final scene of ‘Casablanca’ the DC3 in the background is a scale model, with ‘short people’ as the engineers- an early example of ‘forced perspective in movies- see you FotR commentary for more on this.  It works not because film/TV in monocular, but binocular vision is only used within arms reach, close enough for the eyes to get different signals. 

The brain relies on perspective at anything further.  Remember this next time you fight a Cyclops in D&D;- it shouldn’t get a minus for missile weapons- however it should get a minus in melee.  I have played LRPG, and fighting by firelight is a nightmare in melee- only half the target is illuminated, so binocular vision doesn’t work.  Range is easier as your brain interprets the known height of a human.

How the hell can this be going clockwise? Are you smoking crack or something… she’s obviously going counter-clockwise… look at the foot and the shadow… damn.

Channeling Consi:

It’s a naked dancer. Who cares which way she turns?

I must be really fucked up. The first few times I looked at her she was spinning counter-clockwise. Then I focused my attention on her outstretched hand and the next thing I knew she was spinning clockwise. Now I can’t see her spinning counter-clockwise.

How the hell can this be going clockwise? Are you smoking crack or something… she’s obviously going counter-clockwise… look at the foot and the shadow… damn.

At first I was only seeing it move clockwise.  However, if you keep your eyes on the space between the foot and the shadow, I found that after about a minute of relaxing my focus, the perspective shifted and it started moving counter clockwise.  A little further “practice” and now I can switch back and forth.

Of course, since it’s an animation, nothing is really moving at all, so that’s the real secret of this illusion.

Double weird. I walked away to get some coffee and when I came back she was spinning counter-clockwise again.

At first I thought; “Counterclockwise, obviously.” Then I scrolled down to see the explanation and could only see the figure from waist down - and she was going clockwise, no question about it.  Scroll back up, and she keeps going either direction with no apparent moment of change.  Freaky.

On another level, what Elwed said.

Duckhugger: You’re right. I completely missed the shadow. I naturally assumed that she was oriented upright, but she’s spinning at a slight angle, leaning away from the camera.

I don’t get what people are saying about switching legs. It’s always the left leg that’s straight down.

Both ways, Close your right eye, then close your left, then close both, Look again and you can almost will the dancer to change directions.

Watch the animation for about five minutes and constantly ask yourself “Which leg does she have extended?” You will find over the course of that five minutes that the answer changes.  Because she is 3D you can always tell which leg is extended.  Whichever way she’s rotating it doesn’t affect how you determine which leg is extended.  You will notice over time that she does extend different legs and that those legs correspond with different spins.

Watch for the animation start/stop flicker.  You can see it moving around the axis of rotation.  She changes direction after several ticks.  Short enough that you can “concentrate” and see it change directions.  I saw CCW dance and shadow, CW dancer and shadow (shorter amount of ticks), and CW dance and CCW shadow.  CCW shadow and dancer run the longest.  I don’t trust digital animations like this, you can’t be sure if it’s really doing what someone says.  I have seen the mechanical illusions where rotating objects seem to change direction.

I got a link to a website a while back that supposedly would pick the playing card you were looking at.  It really didn’t, it would show a face card, then pop up other face cards as it’s guess, and fool you into thinking THAT was your card.  Didn’t work if you wrote down exactly what card you picked.

Theocrat: Yes, of course. How stupid of me. When you see her spinning in the clock-wise direction, it appears that her left leg is down, but in the other direction, her facing is opposite, so it’s the right leg.

I can’t see her changing directions though. But I’ve seen other similar animations, where I’ve seen that effect. If you see her that way, she would, of course, appear to change her stance.

I think the shape of the foot should probably be a dead give away too.  After realizing this, I think it’s rigged, but I’m gonna open it in Image Ready to find out for sure…

I opened the gif up in GIMP to look at it frame by frame.  It’s more elusive than I first realized.  It’s only 34 frames long, but actually it never turns around, it rotates back and forth over 180 degrees.  When it gets to the profile view on each side it switches legs and moves back.  Here’s some stills:
Left leg forward:
Frame 2
Frame 31

Right leg forward:
Frame 14
Frame 20

The image does change on it’s own, I sat down with my wife. We both noticed that at the same exact time. She changes...Rigged................

Her body looks clockwise to me but the foot is oscilating - never seeming to make a complete turn.

I think this has more to do with what part of the body you look at than what side brained you are - I mean if you go to a strip club where do you look?

Her body looks clockwise to me but the foot is oscilating - never seeming to make a complete turn.

I watched a video of an uneven rectangle rotating that appeared to oscillate until you looked down at it from above.  The thing about the animations is that you don’t know for sure if it’s really turning in one direction or oscillating, since your brain will usually interpret it the same.

I think this has more to do with what part of the body (boobs) you look at(boobs) than what side brained(boobs) you are - I mean if you go to a strip club(boobs) where do you look?(boobs)

At their eyes.

I did what Bog Brother suggested, and can get her going anti clockwise.  I am with those who say optical illusion, not right/left brain.

The brain tends to see what it’s expecting (a la gorilla in a basketball court experiment- GIYF)*.  Humans tend to act first, and rationalise later, as Scott Adams has mentioned regarding hypnotism.

Clockwise her right foot pointing, anti cw left foot.  I’m guessing that when you first see it the brian makes a snap decision which foot is pointing. Once that is fixed then the rotation of the image is fixed by your knowledge of biology.  The illusion is relying on that as a sillouette each frame could be one of two alignments on a line of symmetry parallel to the viewer- i.e. if she is in the middle of a clock, and you are at 6 o’clock, the ‘mirror’ runs from 9 to 3. So in Frame 14 it is either her left foot pointing to the 2, or her right pointing to 4 o’clock.  If it was posible to set this up with a live model completely in sillouette- flat black, no facing clues- these two poses would appear identical.

So assuming Theocrat is correct (and I’m sure he is) there are only 34 frames what is happening is
Frame one- Pointing to “9 o’clock” (ie 270’).
Frame 34 -p pointing to 3 o’clock/90’ (NB I realise this is different to Theo’s notation- stick wih mine for the moment- westerners think left to right)
Each frame appears to move the foot approx 5 1/2 degrees. (though the distance moved in pixels will be more around the 6 o’clock position)- this is basic moving picture making a la Hollywood- lots of still images giving the illusion of movement.

When Frame 34 is reached it plays them backwards in order, back down to 1.  However because the figure has momentum (or at least our brain ‘knows’ it has) we do not see it as a switch in direction, we see a frame ‘35’ which is identical to frame 33.  Whe one is reached it starts back again.

If can convince the brain the other foot is extended, then it changes direction, because your brain knows to keep the rotation would mean a physically impossible shape.

*BICBB

ragman - :LOL: I generally scan, for me the whole is more than the sum of the parts, the boobs, face, hips, legs all get looked at when I know I can (not the feet), but I look at the floor when I feel embarassed (in public), and so might notice the feet then