Our brains can do amazing things—but in the right circumstances, they can also fool us. Try the brain tricks and teasers below and find out what’s going on in the brain in each one. If you’re looking for more brainy fun, try BrainHQ.

Convex or Concave?
To most people, some of these...
What Do you See?
What do you see in this...
Never-ending Scales
Put on your headphones or turn...
Adelson’s Same Color Illusion
Look at the drawing below. Which...
Hidden Animals
How many animals do you see...
Secret Words
What word do you see here?