Optical Wonderful
Start here
Try four different ways your brain makes sense of what you see. Begin with the picture, then open an explanation to learn what is happening.
-
Ambiguous
Duck-Rabbit Illusion
A single sketch of two bumps and a line reads as either a duck's bill facing left or a rabbit's ears facing right, and most viewers can't hold both readings at once.
-
Size & Perspective
Müller-Lyer Illusion
Two identical lines look like different lengths depending only on which way their arrow-like fins point - one of the most reliable size illusions ever tested.
-
Color & Contrast
Checker Shadow Illusion
Two squares on a checkerboard, one inside a cast shadow and one outside it, are rendered in the exact same shade of gray - yet almost nobody can see that without proof.
-
Geometric
Penrose Triangle
A closed loop of three beams that each look like an ordinary 3D bar in isolation, yet together describe an object that cannot exist in three dimensions.
Ready to explore more?
Browse all 36 entries by topic, or go straight to the interactive demos.