Optical Illusion

(click picture for larger view)

Close one eye. Fix your gaze on either the top or bottom "X". View from a distance of about 80cm. Gradually move toward the screen while keeping your gaze fixed on the X. The eye pictured on the same side as the eye that you are using is the one that will disappear as you move toward the screen. The disappearance will occur when you are gazing from about 45 cm. and the projection falls on your blindspot. Hold your viewing distance constant and glance at the object that disappeared. You will see it when you look at it, but will not see it when the projection from it falls on your blindspot. The top figure works well on high resolution monitors and the bottom figure works best for low resolution monitors.