All optical illusions
28 original illusions, each with an explanation, history and a way to reveal the trick.
Motion illusions
Motion illusionsRotating SnakesDiscs that turn on their own, even though nothing moves.
Motion illusionsOuchi IllusionA checkered disc that seems to float and slide over its background.
InteractiveMotion illusionsMotion Aftereffect SpiralWatch a spinning spiral for 30 seconds and still things start to move.
InteractiveMotion illusionsStereokinetic RingsTurning flat circles that suddenly pop out as a cone or tunnel.
InteractiveMotion illusionsTroxler FadingStare at the cross and the soft colour spots vanish into grey.
InteractiveMotion illusionsMoiré PatternsTwo sets of rings overlap and phantom waves sweep across them.
Motion illusionsPinna-Brelstaff RingsMove your head toward the dot and the two rings turn opposite ways.Geometric illusions
Geometric illusionsCafé Wall IllusionPerfectly parallel rows of tiles that seem to tilt into wedges.
InteractiveGeometric illusionsMüller-Lyer IllusionThree identical lines that look clearly different in length.
Geometric illusionsEbbinghaus IllusionA circle among giants looks small; among dwarfs it looks big.
Geometric illusionsPonzo IllusionTwo equal bars on converging rails look like different lengths.
Geometric illusionsZöllner IllusionShort hatches make long parallel lines seem to tilt toward each other.
Geometric illusionsFraser SpiralConcentric circles of twisted cord that look like one big spiral.
Geometric illusionsHering IllusionTwo straight red lines bulge apart over a burst of rays.
Geometric illusionsPoggendorff IllusionA straight diagonal looks misaligned where a bar crosses it.
Geometric illusionsJastrow IllusionTwo identical arcs, but the lower one always looks bigger.
Geometric illusionsKanizsa TriangleA bright white triangle appears from nothing but three cut-out discs.Brightness illusions
Brightness illusionsHermann GridGrey smudges flicker at the crossings of a black-and-white grid.
Brightness illusionsScintillating GridWhite dots on a grey grid seem to flash with black spots.
InteractiveBrightness illusionsCheckerboard Shadow IllusionA dark square in light and a light square in shadow are the same grey.
InteractiveBrightness illusionsSimultaneous ContrastA uniform grey bar looks lighter on the left and darker on the right.
InteractiveBrightness illusionsCornsweet IllusionLeft and right halves are the same grey, but the left looks lighter.Colour illusions
Colour illusionsMunker-White IllusionThe same pink looks like two colours on blue and yellow stripes.
InteractiveColour illusionsAfterimage FlagStare at a cyan, black and yellow flag and a red, white and blue one appears.
Colour illusionsWatercolour IllusionA thin orange edge tints a whole white region pale orange.Impossible & ambiguous figures
Impossible & ambiguous figuresImpossible TriangleThree bars meet at right angles to form a triangle that cannot exist.
Impossible & ambiguous figuresNecker CubeA wireframe cube that flips between two orientations.
Impossible & ambiguous figuresRubin VaseA golden vase, or two dark profiles facing each other.