How the portal illusion works

This is a development of the barber pole illusion and is related to a few other illusions like the Mephisto Spiral (the spirals that won't come apart), the illusions ring and the rolling rings illusion.

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[SteveMould]

The spirals that won't come apart, that's called a Mephisto Spiral. Forgot to mention that!

[tommydowning]

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.

[Fantasmister]

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).

[_B.C_]

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.

[Nicofaster]

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

[sladewilson]

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.

[Mwstmrlnd]

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.

[ardynizunia]

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.

[TheBitGuy]

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

[FirstDraftPhilosopher]

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.

[peterk]

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

[peachblossom]

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)

[ryxiewuff]

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.

[iau]

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.

[ludoviajante]

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.

[jackglossop]

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.

[josephwodarczyk]

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.

[blargo]

That three-colored-spirals variation is amazing. Unless I block out all but a narrow section near the base, I can't see it as rotation at all. I also like the changing orientation of the cardboard over the diagonal lines. It takes a moment for my brain to catch up and interpret the lines as moving in a different direction.

[colindawson]

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.

[AdamRobertshaw]

Wow, very cool when you changed the overlay on the stripes, for a second at least my eyes still saw the previous movement, then about a second or so of the movement slowly correcting to the new assumed path!