## Long and short

Which horizontal line is shorter: the top or the bottom? Trick question – they’re the same size, even though your mind perceives the one with outward wings to be longer.

## Hypnotising

Looks like the background is spinning around a circle, but both are staying completely still.

## Moving right along

It looks like the background underneath the sphere is moving downward, like a conveyer belt or a slow treadmill. But it’s a completely still image!

## Ripple effect

Are you sure the circles in this image aren’t moving? Are you sure they’re not rippling in a wavelike motion? But really – are you positive?

## Connected lines

Which of the two lines on the right side of the grey rectangle connects to the one on the left side? As you can see from the image on the right, it’s the one on the bottom (labelled in blue) – not the one on the top! When you can’t see the whole picture (literally), these optical illusions can seriously throw you for a loop.

Give your brain even more of a workout with this mind-bending logic quiz.

## Wacky squares

Some of these optical illusions make your head spin! In the optical illusion on the left, the red squares look warped and crooked, like something out of a funhouse. But on the right, when the crazy arrangement of black and white lines is faded to almost nothing, you can see that the red squares are actually as straight and square as can be.

## Squiggly squares

The lines that make up these squares are completely straight – yes, all of them, even the ones in the middle! The placement of the miniature squares-within-the-squares warps the lines and makes them look curved.

## Bending lines

These red lines might look curved outward – but they’re completely straight! This and the next seven before-and-after images are courtesy of Lenstore, inspired by their mind-boggling “In Perspective” project showcasing optical illusions like these.

## How many colours?

Can you figure out how many colours are in this image in total? Did you guess four? Turns out it’s only three! The square in the upper right of this image looks like it contains blue and pink stripes; the one in the lower left seems to have green and orange ones. But, believe it or not, the “blue” and “green” are actually the exact same colour! (Click the “reveal” button in the link!)

## Grey area

Which of the labelled squares is lighter in colour: A or B? This one’s quite the trick: They’re actually the same colour! It’s just the shadow of the green cylinder that makes them look like different colours.

Try these 21 brain games guaranteed to boost your brain power.