Instructables

Which Direction Does She Spin?

Check out the optical illusion below. Since the figure is totally black, there's no depth- you can see her spinning either clockwise or counter-clockwise. Which way do you see it first? Try reversing the spin direction- moving your finger in a circular motion at the rate of rotation can help you reset. How easy is do you find it to swap perspective? Does it make your brain hurt?

Picture of Which Direction Does She Spin?
FFVIIBOY4 years ago
dude i was just looking at this and she was counter clockwise and all of a sudden she stopped and went the other way!
Wait a sec... what about the shadow? It would only appear on the back side so then she really is moving CCW.
Not if the light comes from behind...
Well, the light is coming from behind, but that doesn't change anything.
If you look at the shadow, then the rotation of the figure. Get it to reverse, and watch the shadow again. It moves nearly straight across so whether it "goes behind or in front" is how you perceive it, since this is a flat 2 dimensional figure, it really only oscillates back and forth and does not go around in either direction. I can see this especially with the lowest foot and the shadow. Granted, I have an odd sort of perception when it comes to many optical illusions. Most times, I can "flatten them out" and perceive the actual 2 dimensions only", but this has it's disadvantages. Often I misperceive "real space" and my depth perception is sometimes off. Parallel parking is a nightmare.
The shadow does not move straight across. If it did, it would appear for the entire animation. In fact it carves out an elliptical shape.

The fact that the shadow only appears during half of the animation means that during that half the foot is further away from the camera and is able to cast the shadow. I think this effect is lessened because she rises during that half, but it's still there.
Yes, but the curve is slight enough that one can perceive it moving in either direction since the curve would be equal no matter which "side to side" movement one observed. I know, it is hard to break free of the illusion of depth, and just see the figure move back and forth (that is, switching directions continuously). It requires one to alter the "starting point" with each half cycle of oscillation. Believe me, it "can" be seen as moving in both direction :-)
You don't see enough of the reflection to interfere too much with reversing the rotation, but if you actually did see more of it, it would be more difficult.
As it is, it actually helps me "reverse the direction" of the imagined rotation; that and the lowest foot.
i know about bad depth perception... born blind in my left eye.
Oh my, I am sorry. Mine has to do with the way my brain interprets the surroundings...I CAN override it with training, but the world is really a strange place "visually" to me. The optical illusions that I have seen over the years, can be wiped flat, and those pictures hidden in the color dots (I forget the name of them), some days I can see them right away, and some days I can't see them no matter how hard I try. If nothing else, I am able at times to see things I wouldn't normally see.
That's not a shadow it's a reflection. Cheers, Pat. Pending
Doesn't change anything, though, as it implies the same thing.
I'm not sure I get what you're saying, the reflection seems (to me at least) to be consistent with rotation in either direction. Cheers, Pat. Pending
Yeah, you're right. The reflection gives it away. Crop that out, however, and you'd be cookin wit grease!
By concentrating on the foot of the supporting leg, I can now get it to switch at will - at least most of the time. Pat. Pending
trebuchet037 years ago
So what does it mean when it's easy to swap perspective? I love illusions like this :) On occasion, I've been able to swap without blinking - sometimes it helps to look in a different direction while keeping it in peripheral vision (which works better with movement). And what does it mean if the "default" is always in one direction? That is, do something else for a few minutes and come back -- does it always spin in the same direction at first? For me, it appears to be yes - and CW. Thanks for posting :)
Both the right and left hand are moving is the clock wise direction. Remove the clock fromt he wall and keep it on the floor and observe it and compare it wihtt he illusin given here she is spining clock wise
she is spining in the clock wise direction
Does it matter which way she spins? how about a name, or a number?
Hmmm... I've got it going CW and CCW, but the most amusing thing to do is to blink your eyes at a constant rate, and make it go backwards..... which is really forwards....... interesting....
I saw it CW at first, and had a few glimpses of CCW...this is creepy, but doesn't hurt my brain...at all...weirdos.
I just tried it with my mom...we see it switch at the same time..we think it's switching on it's own.
canida (author)  Weissensteinburg7 years ago
Just wait- you can both see it spinning in different directions at the same time. It's easier for me to make the switch if it hangs for a second, which is probably what's going on for you and your mom.
No...it was spinning constantly, and at the same times, it would appear to switch.
its not, i just opened it up to see. no switch she just spins.
Nor mine and I was able to "stop the spinning" altogether, and just watch her oscillate back and forth.
its a lion7 years ago
i was about to say that i can only see CC, but then she started spinning clockwise... thats a great illusion. too bad i cant hang it on my wall with the other.
Goodhart7 years ago
I find this an easy way for me to "reset", if I scroll the image down so I only see the upper half, she spins one way, viewing the whole figure reverses it. Weird thing is; if I look away, look back and she is spinning differently then before while view the upper half, viewing the whole figure helps reset it the opposite way anyways. Looking at it too long, and it appears only to be moving back and forth, and not spinning at all. :-)
AAAAAAAAAAAA getting dizzy uh oh (barf) lol
crestind7 years ago
I can only see clockwise
That's a really good illusion. I have seen this before with rotating cubes, but this is far more effective. Cheers, Pat. Pending
Easy Button7 years ago
Um I can only see it spinning right\counter clock-wise. I'm getting kind of dizzy.
theque7 years ago
oops i mean cw first then i was able to switch to cc
theque7 years ago
at first i see her spinning right, then i was able to switch the direction of spin. Gave me a bit of a headache trying though XD
I only see it moving CC. OK, my head hurts and I need to print some stuff.