An optical illusion has me perplexed yet again. We've seen so many optical illusions at Creative Bloq, that they should no longer faze us. A horse that rotates in two directions simultaneously? Seen that. Squares that look like they're moving but are actually stock still? We've seen dozens of them.
And yet here's another optical illusion that's left me in awe at how it's possible for our perception to be fooled. It shows two circular groups of ovals arranged a little like the petals on a flower. The two groups appear to be moving at different speeds, but we're promised that they're rotating at exactly the same pace. Confused and amazed? For more such mind-benders, see our favourite must-see optical illusions of all time.
The right ring appears to rotate faster than the left one, though the velocity is the same. pic.twitter.com/YnJ9Uh6HvqOctober 8, 2022
Akiyoshi Kitaoka, a Japanese experimental psychologist who studies visual illusions and creates his own illusion artwork, shared the post above on Twitter. The optical illusion shows two rings of shapes rotating counterclockwise. Kitaoka, who teaches at Japan's Ritsumeikan University, notes that "the right ring appears to rotate faster than the left one," and indeed it does.
So just what in the world of mind-bending optical illusions is going on? Well, this one appears to be all to do with phi phenomena. The Phi phenomenon is often used in a more narrow sense to refer to the illusion of movement in still objects that are illuminated quickly one after another, but there's a range of related phenomena. In this case, both objects are moving, but the change in contrast in the shapes in the ring on the right makes it appear to rotate faster.
Kitaoka's followers have been trying to figure it out. "I think the change of colours feels like rotation so speed increases from our perspective," one person tweeted. "I think the right ring resembles a much faster rotation visible through "gaps" in the actual one?" another person suggested.
Yep, we're confused too, but we wouldn't have it any other way. For more gems like this, see our pick of the best optical illusions that we've seen so far this year and our favourite animal optical illusions.