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Explore classic optical illusions. Look, guess, then see why your eyes fooled you.

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About this page & FAQ

About PlayMemorize Illusions

PlayMemorize Illusions is a free perception trainer built around fifty-seven classical optical illusions. Every round draws one scene · a Müller-Lyer line pair, an Adelson checker-shadow, a Café wall, a Kanizsa triangle, a Penrose staircase · and asks a single, grounded question. Which line is longer? Which patch is lighter? Are those lines really parallel? Your eyes lie; the SVG coordinates don't.

Four families, fifty-seven illusions. Size (Müller-Lyer, Ebbinghaus, Ponzo, Jastrow, Delbœuf, Sander, vertical-horizontal, Oppel-Kundt, Shepard tables, Helmholtz squares, Baldwin), colour and brightness (Adelson checker-shadow, Simultaneous contrast, White's, Cornsweet, Koffka ring, Chubb, Bénary cross, Mach bands, dungeon, Kanizsa triangle/square, Ehrenstein disc, abutting gratings, neon spread, watercolour, Asahi, Munker-White, Bezold, Todorović, and the ambiguous/impossible/animated set · Rubin vase, Necker cube, Schröder stairs, bulging checker, Penrose triangle/stairs, devil's tuning fork, impossible trident, Freemish crate, lilac chaser, rotating snakes, stepping feet, motion-induced blindness), orientation and continuation (Café wall, Zöllner, Poggendorff, Hering, Wundt, Orbison, Ehrenstein line, Fraser spiral, twisted-cord, Bourdon, Ouchi) and grid after-effects (Hermann, Scintillating, Extinction). Use the category chip row to drill one family at a time.

Deterministic by construction. Every illusion is a pure function of (category, difficulty, seed) · equal-length lines are pixel-equal, identical greys are RGB-equal, parallel lines are truly parallel. After you answer, a reveal overlay shows the actual geometry and a one-line explanation of why the perception fails, so each round is a tiny lesson in how vision works.

Part of the PlayMemorize family of free brain-training games. Runs entirely in your browser, works offline as a Progressive Web App.

Frequently Asked Questions

Q: How does PlayMemorize Illusions work?

Each round draws one classical optical illusion and asks a single grounded question · which line is longer, which patch is lighter, are those lines parallel, or simply "Got it" for the ambiguous, impossible and animated ones where there is no right or wrong answer. Pick your answer and the game reveals the true geometry (or RGB) with a one-line explanation of why your eyes got fooled.

Q: Which illusions are included?

Fifty-seven, grouped in four families. Size (11) · Müller-Lyer, Ebbinghaus, Ponzo, Jastrow, Delbœuf, Sander, vertical-horizontal, Oppel-Kundt, Shepard tables, Helmholtz squares, Baldwin. Colour and brightness (32) · Adelson's checker-shadow, Simultaneous contrast, White's, Cornsweet, Koffka ring, Chubb, Bénary cross, Mach bands, dungeon, Kanizsa triangle/square, Ehrenstein disc, abutting gratings, neon spread, watercolour, Asahi, Munker-White, Bezold, Todorović, Rubin vase, Necker cube, Schröder stairs, bulging checker, Penrose triangle/stairs, devil's tuning fork, impossible trident, Freemish crate, lilac chaser, rotating snakes, stepping feet, motion-induced blindness. Orientation (11) · Café wall, Zöllner, Poggendorff, Hering, Wundt, Orbison, Ehrenstein line, Fraser spiral, twisted-cord, Bourdon, Ouchi. Grid after-effects (3) · Hermann grid, Scintillating grid, Extinction illusion.

Q: Is "same" always the right answer?

Mostly yes · by design. At higher difficulties about one round in ten is a trap: the game intentionally breaks equality by a few percent so you can't just tap "same" every time. The reveal overlay always shows the real numbers.

Q: Is PlayMemorize Illusions free?

Yes, completely free. No account, no ads, no paywalls. Works offline as a Progressive Web App once loaded.