We can never get enough optical illusions here at Creative Bloq. We love images and videos that boggle the mind and reveal secrets about how we perceive things like shape and light. Today's is a cracker, and it's one that proves that timing is often everything when motion is involved in creating a visual effect.
The crazy circle optical illusion below shows eight white circles within a larger red circle. The white circles in turn seem to form a circular shape that's rolling around the inside of the larger circle. But, believe it or not, the direction that each circle is moving is an optical illusion. This could well be one to add to our pick of the best optical illusions we've seen this year.
This optical illusion was first shared a while back but it's still doing the rounds on social media today. Each of the white circles is actually moving in a perfectly straight line, but when they all move together, it appears that they're moving in a circular motion. How can this be? Optical illusion enthusiast Brusspup shared a video on YouTube (see below) showing how it's done.
By starting with just one circle and adding the others one at a time, it can clearly be seen that each moves in a straight line. Adding lines to mark each circle's path also makes it clearer to see the true line of movement and not be fooled by the illusion. There's also a moment when there are only four balls moving, and they form a rotating square.
In a sense, this one's not an illusion, but a geometric trick. We're not imagining the circular movement, it's just created by an underlying motion structure that becomes obscured. And this optical illusion is all about the timing since it depends on the moment that each ball is released.
As one person explains in a comment on the video, "how you see it just depends on whether you concentrate on the ball, or the circle. It’s caused by the fact that the inner circle rotates at twice the angular velocity of its centre. So, at any time, the ball’s movement is exactly twice as much as the circle centre’s movement. And that keeps the ball on its line of destiny."
It's a fascinating example of how motion effects can be built up through geometry to the point that they hide their constituent parts, almost like physical architecture. For more optical illusions, see if you can count how many circles there are in this optical illusion or see our selection of must-see optical illusions to bend your mind.