The Optical Illusions Thread

Sid

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The wagon wheel effect/Aliasing

A 'Brain Sync Disc' ~ really impressive. I think it's got to do with our brains clock-time (mind registering time), so that each time one of those patterns happen to fall into our timing zone, it suddenly becomes synced.
 

Mythopoeika

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A 'Brain Sync Disc' ~ really impressive. I think it's got to do with our brains clock-time (mind registering time), so that each time one of those patterns happen to fall into our timing zone, it suddenly becomes synced.
Yep. If you focus on one of the circles in that disc, the pattern then seems to go backwards.
It seems to be dependent on speed of rotation.
 

Amergin

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A 'Brain Sync Disc' ~ really impressive. I think it's got to do with our brains clock-time (mind registering time), so that each time one of those patterns happen to fall into our timing zone, it suddenly becomes synced.
Surely this is just caused by the camera frame rate?
 

brownmane

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Surely this is just caused by the camera frame rate?
I didn't notice the frame rate. I could willingly see the spin direction change when I decided to change my perception. And could change my perception back immediately, or several seconds later. Of course the only time I could do this was once the lines for each row became apparent to me ie the spin rate slowed.
 

Sid

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Surely this is just caused by the camera frame rate?
Probably in this video, it has more to do with 'the wagon wheel effect' than brain! However, recall what happens when you watch a cars wheel turning in motion - at certain speeds, it will appear to go backwards; forwards (normal), or appear to stop turning altogether. I believe the principle is just the same ~ both with eye (message to brain:pop:), or with camera :sbump: frame rates.
 

Sid

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Actually ~ loosely connected to this thread (this might have to be placed under different heading ref?), I discovered something along the same lines, but with sound!
I was passing by my switched on upright fan on a stand after taking a shower, and I happened to notice ~ as I was whistling at the time, that the sound seemed to take a sudden 'wagon-wheel-effect,' but in the sound deflection!
As the blades of the fan are twisted (normal), I wondered if it was the twist of the blade that was distorting and returning the sound in a different form, or/and, as well as how fast the blades were turning, as the returning sound (towards the centre of the fan) itself sounded sort of 'chopped-up,' or 'twisted,' or at least in a different (distorted) form from my original whistled pitch! It was quite a pleasant - different amplification from the sound that I had whistled.
1657006071576.png
 
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PeteByrdie

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This is very good.

I had a couple of these; the t-rex shown here and a dragon. It's basically a hollow face illusion. I found the patterns online somewhere and printed them out. My ex may still have one, I gave my brother the other one. Close up, they work best with one eye closed. They certainly amused everyone at the time. This video may be the first time I saw them.
 

PeteByrdie

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For anyone printing and assembling one of these, I found the 'head' portion sagged over time. I know it's just a novelty but ours hung around for quite a while. A little slither of wood or something similar glued to the back of the neck should help him keep his chin up.
 

brownmane

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For anyone printing and assembling one of these, I found the 'head' portion sagged over time. I know it's just a novelty but ours hung around for quite a while. A little slither of wood or something similar glued to the back of the neck should help him keep his chin up.
What about printing out the template and then gluing it to bristol board to give it better support?
 

brownmane

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This one is very effective as it tends to show perspective - unlike 'the floating cube' (above) whish does not.
I like that one too as I couldn't figure out how the cube's connector didn't cast a shadow. Ingenious that it's attached to your finger so there is only your hand's shadow
 
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