Leaning Tower Illusion

Look at Tower A and Tower B. They are side-by-side. Does Tower B seem to be leaning significantly moreto the right than Tower A?

These images are 100% identical and rotated at the exact same angle.

Discovered in 2007, this illusion breaks our brain'sperspective-correction software.

In the real world, if two parallel towers are leaning away from us, their images should converge as they get higher. Since these two images are identical and do *not* converge, the brain assumes they must be diverging in 3D space. To correct for this perceived divergence, it makes the right-most tower look like it's leaning much harder.

• Comparison: Try putting a finger over the space between the towers. Sometimes breaking the "side-by-side" context helps you see they are identical.
• Symmetry: Does it look different if you close one eye? Usually, the effect persists as it's a higher-level cortical illusion.