Extraordinary. Is there an explanation for this?
Yes.
The human brain tries always to make lines between lines, dots, objects - depending on the relationship with their surroundings.
On the first woman the white lines drawn would only show if she was turning that way as the same for woman 3.
The brain also 'brain maps' shapes, patterns and similar behaviour.
Therefore if you concentrate on either the left or right image then the brain, which can only see/recognise the other images as being similar, will 'mimic' the same pattern hence you will literally think the images to the left or right - depending on which one your are looking at - will all be of a similar shape and therefore a similar behaviour.
Try this, look at your ceiling with the main light fitting just in peripheral vision, and DO NOT look at the light fitting (but you know it's there) and eventually your brain will erase the light fitting and turn it into the regular pattern (colour/texture etc) of the ceiling.
You'll see it disappear until you look for it and then it will reappear - so the trick is to notic it but NOT to look at it.
