They spin, they whirl, they pulsate—or at least that's how it seems. Found across the Internet, these optical illusions use color, design, geometry, and shading to play tricks on your eyes. Some are composed of simple black and white lines while others are made of rainbow colors in a variety of shapes, but all the op art on this list has the power to mesmerize (or at least make you dizzy). Check out The 19 Craziest Optical Illusions on the Internet.

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