A very characteristic experiment can be performed with a black spiral line on a white disk.

If we revolve such a disk slowly around its center, the spiral line produces the impression of a continuous enlargement of concentric curves.

The lines start at the center and expand until they disappear in the periphery.

If we look for a minute or two into this play of the expanding curves and then turn our eyes to the face of a neighbor, we see at once how the features of the face begin to shrink.
It looks as if the whole face were elastically drawn toward its center.
If we revolve the disk in the opposite direction, the curves seem to move from the edge of the disk toward the center, becoming smaller and smaller, and if then we look toward a face, the person seems to swell up and every point in the face seems to move from the nose toward the chin or forehead or ears.

Our eye which watches such an aftereffect cannot really move at the same time from the center of the face toward both ears and the hair and the chin.