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Plain, well-sorted illusion collection with the explanation directly underneath each one, from café walls to impossible triangles.
Opens in a new tab. We do not control this site and it may have changed since we catalogued it.
BrainDen Optical Illusions sits in Optical Illusions under Weird, filed as coffee break.
About this category: Illusion collections and perception demos. The good ones keep working after you have been told exactly how they work.
Yes. BrainDen Optical Illusions is free to use and needs no account.
No. You can use BrainDen Optical Illusions without signing up for anything.
Yes. BrainDen Optical Illusions works on phones as well as desktop browsers.
Yes, we file it as safe for work. It also works muted.
We file it as "Coffee break": Five to fifteen minutes of proper attention.
Interactive classroom illusions you can drag, toggle and pause, which makes the effects considerably harder to dismiss.
Tim Rowett's collection of optical toys and physics oddities, each demonstrated on camera by a man visibly delighted with all of it.
A philosophy department's catalogue of illusions, each with what it is, what it demonstrates, and the argument still going about it.
Catalogue of impossible figures, ambiguous objects and Escher-adjacent architecture, kept up by one very devoted collector.
Tens of thousands of riddles, brain teasers and lateral thinking problems submitted by users since 1999.
Dual n-back, the working-memory drill psychologists keep arguing about, implemented properly and charted over time.
A scrappy free collection of brain teasers and n-back drills that has been quietly online since long before the app stores existed.
Where the bridge world actually plays: free tables at every hour, tournaments, and teaching rooms of remarkable patience.
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