Thread: Favorite optical illusion?

Originally Posted by DavidP

The motion of the animation supports the fact she is going clockwise anyways...when she faces you she is going from right to left...when is facing away from you, left to right...

That's because you haven't seen it going the other way. It is totally convincing in all aspects in both directions. As I mentioned, if you look at the individual frames of the gif, she actually alternates doing both, going 90 deg one way, 90 back (facing backward), 180 deg one way (to face forward), 90 deg back (still facing forward), etc. Looking at that, you can see how the silhouettes would be/are the same.

It is very difficult for me to get it to switch at will with both eyes but guess what -- it is very easy* if you cover you one eye at a time (with my right eye I see it counter clockwise, with my left clockwise). So it really is "the hemispheres".

* but not quite automatic

Originally Posted by carrotcake1029

I think this page is interesting:
The Right Brain vs Left Brain test | PerthNow

Interestingly,that illusion was discussed here back some time.

Originally Posted by stevesmithx

Interestingly,that illusion was discussed here back some time.

Hmph. So it's not really about right/left hemisphere, according to wikipedia.

I'm gonna update my right/left eye conjecture slightly: you can force the dancer to reverse by scanning your eye in the correct direction when the foot is at the limit of it's right to left arc, and it's easier for me to "intuitively" scan that way using one eye (and easier to scan from inside to outside, so right is the opposite of left). Probably this is because in the gif frames, the change in direction occurs when the foot is all the way to one side. I think probably the frames were rearranged form a normal 360 deg revolution. They are all up at wikipedia, you can see she looks like she is swinging side to side, back and forth, not all the way round (180 + 180).

I bet that would be hard in bare feet