The Spiral That Isn’t
A twisted cord winding in towards the centre. Or four circles.
How to play
Look first, then answer
A twisted cord winding in towards the centre. Or four circles.
- Under a minute · one question · then the explanation
How it works — best read after you have tried it
A spiral assembled from tilts
There is no spiral: the cords make four separate circles around the same centre. Every short stroke is tilted a little inwards, and the visual system joins those local tilts into one path that keeps turning in — a spiral nobody drew.
The British psychologist James Fraser described it in 1908. Follow a ring with your finger and it comes back to where it started; let your eye run along it and it slides inwards again.