An optical illusion created by Twitter user @jagarikin shows two cubes (above) that seem to take orders from the arrows inside of them. When the arrows point in opposite directions, the cubes move away from each other. When the arrows curve and spin, the cubes spin as well. But in reality, it's just an optical illusion — these tricky cubes are actually completely still.
If you don't believe me, stare at just one corner of a cube, blocking the rest of the picture with your hand. Yes, it's flashing, but it's not moving.
The illusion is based on the visual concept known as Reverse Phi. To put it simply, when our brains notice things transitioning from light to dark they perceive it as motion. As the cubes' edges alternate from white to gray to black, our brains believe that they are rotating.