Sometimes a purely static image will appear to be moving because of some design feature.
That’s not what I’m asking about.
I’m asking about an illusion that arises only through real movement involving patterned objects. This movement can be supplied by the movement of one object with respect to another; or the movement can be supplied the changing point-of-view of an observer moving past two objects that are stationary with respect to each other.
For example, sometimes as you pass a fenced yard along the north edge, you look at the north face of the fence, and through the gaps in the fence you can see the west face of the fence. As you pass, the two faces seem to move with respect to each other (a phenomenon known as parallax – also not exactly what I’m asking about) and something weird seems to happen. This weird thing – exactly what I’m talking about – seems to be a pattern of light and dark with contours different from those of the real fence. You can sometimes see curves where you know all of the real objects are straight, and if you just stop moving for a moment the illusion also stops and you see things as they are.
I believe that I’ve had a similar experience with hubcaps and with circular fans, which can appear to spin backwards or at the wrong speed.
I would be interested in any clear name or description of this experience, and further examples if you've got 'em.