This hurt my brain

· · Mastodon Twitter Crossposter · 30 · 220 · 238

Here's how it works.
It's easier to see on this alternative version. Thin inner and outer rings are offset +/- 45 degrees from the main ring. Our brains subconsciously connect the leading edge (inner or outer) to the main circle and follow through with the trailing ring.

This creates a paddlewheel effect. For a single-direction motion effect, these tiny rings are hidden on the non-moving axis.

Notice how they fade away at the top and bottom? And how the inner and outer rings are reversed on opposite sides of the same ring?

@Andy_P but… how?! I guess, the mystery could be solved by measuring sizes of both disks, frame by frame. or just by erasing arrows. %)

@fuzzylynx I’m not on a pc to check frame-by-frame but I suspect the thin inner and outer rings around the big colorful ones are probably changing somehow to cause the effect.

Because the illusion still works if you cover the arrows, so it’s more than mere suggestion

@Andy_P @fuzzylynx
Your brain receives/interprets different colors at different speeds.

@fuzzylynx @Andy_P with piece of paper put on screen, it seems the size and positions of discs remains almost unchanged

@miklo @fuzzylynx @Andy_P The shape, position and size doesn't change. The large portion of the ring doesn't even change it's spinning color pattern. Only the thin colored rings on the inner and outer edge change their color gradients.

@lbehm @miklo @Andy_P so, after eliminating of almost all possible causes, it’s safe to suppose that the illusion is caused by those thin rings. and I guess it’s their brightness (much more than the color) which affects our perception the most. since the background is neutral gray, gradual change in brightness of outer and inner thin rings in opposite directions gives us an illusion of moving borders of main rings.

@Andy_P I had to check with my fingers to make sure they were really moving! They are, but much more slowly than the colors are spinning, so it's not a trick, but it might be trying to pretend it is. :)

It seems just the border pixels are giving the feeling of movement. In the direction it seems to move you can see a white border 1 pixel width that is not visible on the border where the movement is transversal.
Hope I am clear.

@coq @Andy_P I'm viewing on my phone and used my fingers to test for gray spaces showing while my fingers remained static. It's more than just that. XD


that's pretty cool imho..

any clue how was it done or who did it?


@ahanon I opened the frames up in photoshop to unlock its magic. Explainer posted above.

@Andy_P my graphics program does this to me all the time!😭

@Andy_P it even work when covering large parts of the image 😳

@Andy_P Any idea how it works? I’m trying to reproduce it with CSS but can’t achieve the illusion as I don’t understand it. :(

Spend an hour toying around it, failing.

@meduz You should be able to do this in CSS, see my analysis reply to my first post. Opening the frames in an editor reveals its secrets.

@Andy_P @e8johan I felt so much better before it finished loading and was just a static image.

👍 Latéralisation, rythme et propriétés spaciales de la couleur (rouge=près bleu=loin) + petit trick sur les "bordures" en relief (accentuation).


Oh wait, it took me a minute to realize that THEY ARE NOT MOVING

@Andy_P This took me an awful long time to prove to myself that the circles were not moving

Tried. Didn't work.
Checked error code: brain in standby/hibernation mode

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