How the portal illusion works

The spirals that won't come apart, that's called a Mephisto Spiral. Forgot to mention that! The sponsor is Incogni: The first 100 people to use code SCIENCE at the link below will get 60% off: incogni.com/science

Am I the only one who NEVER before this video thought that barber poles were supposed to create an illusion? For over thirty years I always saw them as just spinning around.

I'm a middle aged British guy too - the TV show you're thinking of is Terrahawks, the hoops were on Zelda's desk. Also in Superman 2, and an episode of Seinfeld where they're made of tyres, and Elaine's clapping them (I think it's the episode where she turns stupid due to lack of how's your father).

It works in music too! If you loop three chromatic scales stacked an octave on top of each other (C2, C3, C3) going up, it will sound like it’s going up forever. As well as going down it will sound like it’s going down forever.

i never even once got confused by the barber spinning thing, i always saw it as a cilinder spinning which happened to have a spiral pattern, latter in my life i just assummed it was because bright colors + motion = attention, never even considered the possibility of it being an illusion of a thing that goes upwards forever. now the spirals and the 3 ribbons absolutely fried my brain, my brain was trying so hard to figure a way in which it would make sense and ignored the possibility of rotation, the 3 ribbons specifically, having 3 separate ribbons spinning individually is absolutely genious

So weird. Your brain just changes mid rotation. I never saw those barbershop polls as anything but twirling until this video when all of a sudden it look like an elevator. You rock Steve. Don't ever change.

The illusion is so effective that for the first 10-20 seconds, I genuinely couldn't figure out what the illusion was. My brain just accepted it immediately. Super convincing.

The 3 ring illusion was also used in Superman with Zod (1980s?) if I remember. Its illusion I believe is based in our familiarity with mirrors and reflection; my brain sees it as a ring that fell and is settling on a glass table. These illusions are all good examples of frame of reference in physics.

In the merchant navy this used to be known as the “anchor curse,” a man watching a cable disappear through an Haweshole could be mesmerised by the apparent spinning motion of the rope, this could send sailors into a trance and cause them to act strangely such as stealing alcohol from the ships kitchen or smashing up a bar in Gibraltar with six mates. My Grandfather was sadly afflicted with the curse and blames it to this day for his truncated naval career.

The 3 spirals rotating at different speed is absolute genius. I could have never figured it out myself and still can't see them as rotating.

The three rings illusion is the initial cell that General Zod is held in during his trial at the beginning of Superman (1978).

I actually think it looks even cooler when the spiral is removed from the assembly, because to me it looks like the top part disappears into thin air, like theres a crack in spacetime above it or something.

Hi Steve, the tv show you’re thinking of was Terrahawks. With the cube robot baddies and sphere goodies (Windsor Davies) which played naughts and crosses at the end. I was always fascinated by the spinning illusion too. (Just noticed others mentioned it earlier…oops)

I basically can't stop squealing at seeing my stuff on your channel. The "ends disappearing into the cavities" thing is actually one of the hardest tradeoffs in designing these. The illusion works best if the helixes are very eccentric and detailed, which requires more radius. But the wider the bottom cavity is, the further down it you can see, so you have to make it deeper to compensate. That means more "wasted" helix, and you can only print the helixes as tall as your build volume (trying to "stitch" multiple helixes end to end would leave a seam and spoil the effect). So there's a lot to juggle when trying to squeeze as much out of the effect as possible.

My favorite types of illusions are the ones where, even knowing how they work, I still cannot make my brain see the reality of the situation.

The version with 3 colors is downright convincing. I thought rotation would be the most obvious illusion, but I straight up ruled it out as impossible because of the shape.

I saw the 3 ring illusion as part of the Rani's Tardis in Doctor Who.

This is fascinating! Even knowing what the image looks like, knowing that it's rotating, knowing how the illusion works and why my brain is fooled, I still can't see it any other way.

The spinning thingy, that you mentioned was used in the original Superman movie surrounding Zod when getting sent to prision. It was also used in Terrahawks, by Zelda, she had it spinning around a crystal.

I appreciate that you always show the illusion or physics thing at the beginning of the video. Really easy to show other people that way.