40 illusions · drawn live · a new one every day
Optical illusions you can take apart.
Every illusion here is drawn live. Move the sliders, switch the trick off to see what is really there, and find out why your brain fell for it.
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Illusion of the day
A different one every day. Same one for everyone, so you can compare notes.
Size and shape
Size and shapeCafé wall illusion
Rows of black and white tiles make perfectly straight, parallel lines look like wedges.
Size and shapeDelboeuf illusion
A disk inside a snug ring looks bigger than the same disk inside a wide ring.
Size and shapeEbbinghaus illusion
An orange circle looks smaller among big circles and bigger among small ones.
Size and shapeFraser spiral illusion
Separate circles look like a spiral, because of tilted stripes.
Size and shapeHering illusion
Two straight lines seem to bow outward in front of a starburst.
Size and shapeJastrow illusion
Two identical curved shapes: the lower one always looks bigger.
Size and shapeKanizsa triangle
A bright white triangle appears where there is no triangle at all.
Size and shapeMüller-Lyer illusion
Two lines of exactly the same length look different because of the fins at their ends.
Light and color
Light and colorBenham's top
A black and white disk shows pale colors when it spins.
Light and colorChubb illusion
The same patch of texture looks less contrasty inside a busy surround.
Light and colorColor assimilation
The same red looks pink on one side and orange on the other.
Light and colorCornsweet illusion
A thin edge makes two identical grays look like a light half and a dark half.
Light and colorEhrenstein illusion
Bright discs appear where the lines stop, though nothing is drawn there.
Light and colorHermann grid
Gray spots flicker at the crossings of the white streets, except where you look.
Light and colorMach bands
Each strip of gray looks shaded, lighter at one edge and darker at the other. It is perfectly flat.
Light and colorNegative afterimage
Stare at an oddly colored picture for 25 seconds, then see it in different colors on a blank screen.
Motion and two-way pictures
MotionBarber pole illusion
Diagonal stripes moving behind a window seem to move along the window instead.
MotionMotion aftereffect (waterfall illusion)
Watch a spinning spiral for 30 seconds; when it stops, it seems to turn the other way.
MotionMotion-induced blindness
Three bright yellow dots disappear while a blue pattern turns behind them.
MotionOuchi illusion
A circle seems to float and slide over the background when you move your eyes.
MotionPeripheral drift
A still pattern seems to rotate in the corner of your eye.
MotionPinna-Brelstaff rings
Two rings of squares seem to spin in opposite directions as the picture zooms in and out.
MotionStepping feet
Two bars moving at the same steady speed seem to take turns stepping, like feet.
MotionTroxler fading
Soft colored blobs fade away into the gray when you keep your eyes still.
Guides
How Strongly Are You Fooled? Take the Illusion TestMeasure how strongly optical illusions fool you: set the lines in the vertical-horizontal illusion until they…
Optical Illusions for KidsTen easy, safe optical illusions for kids to play with online, each with a simple explanation and a quick cha…
Printable Optical Illusions Worksheet for the Classroom (Free)A free printable optical illusions worksheet: 10 classic illusions with a question each and an answer page, r…