exhibit demonstrates how eye motion is affected by looking at moving
stripes. Closing one eye, the visitor watches the stripes on the
inside of a revolving drum. With a finger placed gently over the
eyelid, the closed eye can be felt moving back and forth. Watching
the moving stripes, the open eye briefly follows one stripe and
then snaps back to catch the next one. The constant tracking motion
keeps the perceived image from blurring. The eyes move together
so the closed eye moves as the viewing eye moves.