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- This might be my new favorite illusion.
When I grab this thing and pull it upwards,
these spiraly things in the middle seem to disappear
into the top of the assembly.
At the same time, new bits of the spiral
seem to be generated from the base.
Up and down it goes, appearing and disappearing.
Here's another one, and look
there's an infinite amount of spiral.
I can just keep going, pushing more, and more,
and more into that black hole at the top,
and there's a never-ending supply coming out of the bottom.
I don't think this illusion has a name yet.
It's related to the barber pole illusion,
but it's different in an important way,
which I'll get to in a minute.
So, I think it deserves a name of its own.
I've been calling it the portal illusion.
In fact, you know what?
Let's put some LEDs in there.
By using orange and blue LEDs,
I can evoke your memory of the game "Portal".
So now it seems as though this spiral
that disappears into the top
is the spiral that comes out of the bottom.
By the way, this was designed by Ada Cohen.
I'll leave a link to their stuff in the description.
This design is perhaps the easiest to see what the trick is,
if you haven't worked it out already.
If I pull it apart, here's the spiral.
And look, if I turn the spiral in my hands,
you get the same effect.
The illusion doesn't work as well, of course,
and that's interesting in itself.
When the spiral is back in the assembly
and the turning of the spiral is done,
not by spinning with your fingers,
but by moving this piece up and down.
Well, the motion of this piece
matches the illusionary vertical motion of the spiral.
So the motion of this part enhances the illusion.
Also, the fact that you can't see the top
and the bottom of the spiral, those ends seem to fade away
into the darkness of those cavities there.
That's got to play a part in the illusion as well.
Basically, if you look at a segment
of the spiral in isolation,
rotary motion is indistinguishable from lateral motion,
and that's like the mathematical definition
of a spiral, right?
Or perhaps more correctly a helix.
A rotation of the spiral is equivalent
to some vertical displacement of the spiral.
So, your brain has to decide which one is it,
and obviously it uses external clues
to figure out which one it is,
or at least to make an educated guess.
A few related illusions that I really like are this one.
Your brain tells you
that I'm pulling these two spirals apart
and yet they never separate.
In fact, the overlap between the two spirals
seems to stay the same.
And then there's this one, an illusionary ring.
As I move the ring around my finger,
it appears to either grow or shrink
depending on which direction I turn it.
I also found this design, which I printed out myself
now that I finally have my own 3D printer.
When this one spins, it looks as if the rings
are rolling around on top of each other,
and then your brain has to contend with the question
of how are these things balancing so well?
Again, your brain would rather assume vertical motion
than rotating motion.
Actually, this particular one is driving me mad
because there was a kid's TV show back when I was a kid,
I'm pretty sure it was puppets,
but it wasn't "Thunderbirds,"
and the batty in it had a sculpture like this one.
But I, just for the life of me,
can't figure out which TV show it was.
If you have any ideas, let me know in the comments.
So what's going on in your brain
when you make an incorrect deduction
about the way the spiral is moving?
Well, there's a lot of information out there
about the barber pole illusion,
so let's have a look at that.
It's a really similar idea.
A spiral rotates, but it looks like it's moving.
You don't even need a spiral for this to work.
Look, here I've got some stripes.
You could say these diagonal stripes are moving downwards.
Or you could say they're moving to the right,
or you could say that they're moving diagonally, this way.
In fact, all of those possibilities could be true
and there would be no way to distinguish one from the other.
But I can actually nudge your brain
into choosing one of those possibilities.
By laying this rectangular aperture
over the top of the moving stripes, I can bias you
into thinking that the stripes are moving downwards.
Or look, if I rotate the aperture
so it's lying horizontally,
now I've biased your brain
into thinking the stripes are moving to the right.
Why is that?
Well, your brain is looking for clues,
and look at this point here
where the stripe meets the edge of the aperture.
That point appears to be moving to the right.
This point here appears to be moving down.
But look, there are six points all moving to the right
and two points moving down.
There's a lot more evidence
that the stripes are moving to the right
than there is evidence that the stripes are moving down.
And the opposite happens
when you switch the aperture to vertical.
Well, if the aperture was a square or a circle.
interestingly, in this situation your brain decides
that the stripes are moving
at the slowest possible speed.
That is to say they are moving perpendicular
to the direction of the stripes, this way.
An actual barber pole is different
to these stripes,
in as much as the underlying ambiguity is different.
With stripes, there's no way to know whether the stripes
are moving down, or to the left, or indeed diagonally.
Whereas with the barber pole,
you're choosing between two specific things,
which is rotational motion and translational motion.
I believe that these things improve
upon the barber pole illusion
by giving these spirals a more complex profile.
Like, with a really simple spiral,
like the one in a barber pole,
it's really obviously a spiral.
Whereas I would say,
with a more complex profile like this one,
it's not immediately obvious that rotational motion
is equivalent to translational motion.
Because I'm new to 3D printing and I dunno what I'm doing,
this long part was wobbling near the end of the print
and you can see that in the lumps and bumps here,
which, if you look carefully, you can spoil the illusion.
You can see that the bumps are moving horizontally
instead or vertically.
That's why I'm filming this with a long exposure.
Long exposure causes motion blur
and the motion blur helps to hide those lumps and bumps.
This one was printed with support
so it's a lot smoother at the top.
This one also has an additional illusionary trick
which is that the three spirals aren't all twisted
to the same extent.
This spiral goes through two full twists from top to bottom,
whereas this goes through only a half twist.
This spiral twists in the opposite direction
to the other two.
That means that rotating all three at the same time
is not equivalent to some vertical displacement.
So, your brain is even more likely
to rule out that possibility.
That's my hypothesis anyway.
In fact, sliding this black thing up and down
causes the three spirals to rotate independently
of each other at different rates.
It's a really clever design.
What about these spirals that could never be pulled apart?
Well, it's the same thing.
It looks as though I'm pulling these spirals horizontally
with my fingers,
but actually I'm allowing the spiral
to slip through my fingers and therefore rotate instead.
It's just really hard for your brain to see it that way,
to the point where your brain would rather believe
the wire is getting longer.
What about this ring?
Well, this is the opposite, really.
The up-and-down motion of the spiral is interpreted
in your brain as rotation of the spirals.
When the spirals appear to be rotating outwards,
it makes it seem as if the ring is growing wider.
When the spirals appear to be turning inwards,
it's as if the ring is getting narrower.
I'm not exactly sure what's going on with this one.
Like, surely your brain should pick the rotating option
over the rolling option.
Maybe it's just because we see this kind of motion
quite often in our lives, whereas this seems
like it shouldn't exist
because the center of mass
is outside of the apparent pivot point.
All these illusions share a theme,
your brain has to choose between rotational motion
and lateral motion.
But this one's still my favorite.
I used to get a lot of these creepy marketing phone calls
where the company knows my name, knows where I live,
and I don't get them anymore.
And the way you get from one to the other
is long and arduous
because there are all these shady companies
called data brokers that are selling your data
to these marketing agencies.
And when those marketing agencies call you up
and they say your name, you think,
"Oh, this must be a company
I've got a prior relationship with," but you don't.
You can make it stop by asking the data brokers
to delete your data,
but there are literally hundreds of them,
and they all want to be contacted in different ways.
You know, this one wants you to fill in a form on a website.
This one wants an email.
And I just know personally
that is not a task I will ever do
and it would take months anyway.
The way I managed to stop those creepy phone calls
was to get somebody else to do it for me.
I'm talking, of course,
about the sponsor of this video, Incogni.
Incogni has done all the legwork,
figuring out who all these companies are,
how they want to be contacted.
They handle that part.
They handle the bit that comes after
when there's a rejection of your request
and you have to appeal.
And I really appreciate a simple proposition like that.
"Is a thing that you want
but don't wanna do yourself?
We'll do it for you.
This is how much it costs.
You decide."
This is the dashboard that shows me
these are all the companies that are confirmed
to no longer have my data.
It's not just phone calls, it's text messages,
paper mail, email, fax.
I dunno,, I've don't got fax, I dunno.
And you know, if one of these hundreds of companies
has a data breach, that data breach doesn't include my data.
But you know, it's a thing that I needed to do
and now it's done and that feels good.
The deal on this one's really good.
The first 100 people to go to incogni.com/science
and use the promo code SCIENCE at checkout will get 60% off.
The link is also in the description.
So check out Incogni today.
I hope you enjoyed this video.
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