Mark Wyner Won’t Comply 
These cubes aren’t moving or changing (as implied by the arrows). At all. Not even a little. Other than the color toggle, they remain constant.
(Credit: Ja Gari Kin)
EDIT: added content warning because of the flashing.
Stevens R MillerThey don't move, but the black/white isn't just toggling. Capture two frames of motion about three or four frames apart and compare them. Here, I've done that when they are appearing to rotate, and put one frame in the upper half, the other frame in the lower half. You can see the gradient.
i.grok@stevensrmiller @markwyner slight movement is movement
I originally thought they moved, but they actually don't. The black/white toggle actually isn't a toggle. It's an animated gradient, but it remains entirely within the same thick lines that define the cubes' shapes.
This kind of "reverse phi" illusion works in a lot of other forms. Never seen this particular example before. They are all based on black/white changes that look to our eyes/brains like motion. Here's an explanation:
@stevensrmiller @markwyner the pixels in my screen aren't moving either, but it sounds less impressive when I put it that way ...
All illusions become less impressive when you know how they work. It's like finding out a magic trick was done with mirrors. Or, as the AI researchers will tell you, it's like finding out "it's just some code."
Still pretty impressive (though this one seems to make me nauseous in only a few seconds, alas).