Zöllner Illusion
Horizontal bars that appear to tilt away from each other at impossible angles.
🧐 What do you see?▼
Look at the long horizontal lines. Do they look like they are tilting toward or away from each other in a zig-zag fashion?
These lines are perfectly parallel and purely horizontal.The short diagonal strokes crossing them are "tilting" your perception.
🧠 Why this works▼
The Zöllner illusion is a classic example of how angles affect orientation perception.
When the brain sees an acute angle (where the cross-hatch meets the main line), it tends to "overestimate" the size of that angle to help distinguish the objects. This overestimation pushes the main line in the opposite direction of the cross-hatch, creating the tilt.
🧪 Try variations▼
- Adjust Intensity: Changing the intensity alters the angle of the cross-hatching. Notice how the illusion becomes weak or strong depending on the angle.
- Focus: Staring at one single line for a long time can sometimes "correct" the illusion.
❓ FAQ▼
Who discovered this?
It was discovered by Johann Karl Friedrich Zöllner in 1860, who noticed it on a pattern in a fabric design.