Op art of the 1960s relied on a physiological effect that creates an illusion of motion. this effect is . the natural oscillations of the eye our lack of ability to see some colors the ability to roll one's eyes back into one's head blinking crying

The op art or the optical art is referred to a visual art, which work on the principles of optical illusion. These are blank and white pieces of the abstract designs, which creates an illusion of movement, vibration and sometimes, a hidden image can be seen in this normal abstract.

The op art seems to be vibrating and moving due to the natural oscillations of the eye. This oscillation is caused by the saccade movement of both the eyes. in this case, rapid movement of both the eyes causes a change in the point of fixation, creating oscillations.

So, the given blank can be filled with natural oscillation of eyes.

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