Video is the best way of showing how strange these can appear -<p><a href="https://i.imgur.com/g5Ot0rH.gif" rel="nofollow">https://i.imgur.com/g5Ot0rH.gif</a><p>Source - <a href="https://www.thingiverse.com/Matsemann/collections/matsemanns-ambiguous-cylinders" rel="nofollow">https://www.thingiverse.com/Matsemann/collections/matsemanns...</a>
This is old enough that the year (2017) should be in the title.<p>Also, the optical illusion isn't really 3d since it relies on a single point perspective - it'll show up on camera, but if you see it with two eyes you'll see the actual structure.<p>Now for a real 3d optical illusion, look at the hollow face illusion - not on video - find a real life instance of a depth reversed face.<p>Your brain has circuitry specifically optimised for facial recognition, and what you're seeing so confuses your mind that it breaks depth perception.<p>It will actually appear as if a static object is turning to follow you around the room.
Cool.<p>STLs?
Would love to print a couple of these for my kid's show-and-tell in class<p>edit: found some , search "illusion" on thingiverse, not "topology" :)<p>eg,
<a href="https://www.thingiverse.com/thing:3169391" rel="nofollow">https://www.thingiverse.com/thing:3169391</a>
Is this the same type of illusion?<p><a href="https://www.youtube.com/watch?v=oWfFco7K9v8" rel="nofollow">https://www.youtube.com/watch?v=oWfFco7K9v8</a>