The Colour Conundrum

This BBC podcast is supported by ads outside the UK.

Booking a trip?

Don't skip the travel insurance part.

Insure My Trip makes it super easy to compare plans that actually fit your trip.

Whether it's a weekend getaway or a semester abroad, we've got you covered.

From cancellations to lost luggage and medical emergencies, no shady providers, just smart tech and real help from licensed agents.

Plus, we don't play favorites.

Just what's best for you.

Be the main character when you travel.

Protect your trip at InsureMyTrip.com.

That's InsureMyTrip.com.

BBC Sounds, Music, Radio, Podcasts.

I'm Dr.

Adam Rutherford.

And I'm Dr.

Hannah Fry.

And you are going to send us your everyday mysteries.

And we are going to investigate them using the power of science.

Science.

Science.

I like it.

Hello, Curios.

This is the final episode of the current run, but we will be back later this year.

I think we're contracted via blood to do this until we die.

Anyway, here's the programme.

Today's question was sent into curiouscases at bbc.co.uk and it comes from 11-year-old Maya Crocombe.

I would really like to know, she says, how we see colour and why some people and animals are colourblind.

Now, this is a very good question, Maya.

This one is very much in my wheelhouse.

Well, hold on there a moment, Adam, because actually we've had more than one question in on this topic about how we perceive colour.

Camille Murdoch also asked, I have an English teacher who is colourblind to red, green, and pink, and I was puzzled why it's only those colours.

Also, a fantastically interesting bit of science as well.

And one more for the pile here.

James Martin also asked, are colours real or just perceived?

Well this is just incredibly exciting for me because this really gets to the heart of the most humanness of being human.

You know, the redness of a cricket ball, the blue of the sky, the orangeness of an orange.

How do we perceive that?

How do our perceptions differ?

What even is colour?

All right, calm down, Aristotle, over there, because we already know that some people people see colours differently.

Some people don't have typical colour vision.

Normally we call this colour blindness and they may well see that green grass or the orange orange differently but it is no less real.

Have you ever tested your colour perception skills?

Not officially although I'm pretty sure they're quite good.

As are judged by your salmon pink jumper right there?

I think it goes very well with my bright orange hair.

Perfectly, I'm sure.

Well look there's lots of different online tests you can do.

Some more credible than others.

The one I want to show you now is called the Farnsworth Munsell Hue Test.

And it's just click on the link that I just sent you.

And it's a set of blocks of slightly different shades.

And we, in a minute, have to arrange them in order.

Okay.

Okay.

So it's a bit like a rainbow.

Very, very bland rainbow.

Is it competitive?

Everything we do is competitive.

Okay, so we'll start the timer.

Now, go.

Well, yeah, it's quite hard.

No.

For me, it's not.

Oh, all right.

I think my computer screen might be a bit dirty.

Sure.

That might be the problem here.

You've done the whole thing?

I've done.

Oh, Lord.

Hold on.

Okay.

There's a button at the bottom which says check your score.

Please wait.

The tension here.

Oh, what did you get?

Two.

So did I!

So it says, the lower score is better.

Zero is a perfect score.

So we're evenly matched then?

Perfectly so.

How terribly disappointing.

Yes, but now we can get on with the episode.

Well, we have two experts with us to guide us through this topic, both from Newcastle University, Professor Anya Hulbert and Dr.

Gabriele Jordan.

Welcome to both of you.

Now, Anya, can you explain the nuts and bolts of vision here?

So let's say that you've got a ray of light bouncing off my jumper and hitting Adam in the eye.

What's actually going on?

So the light that's shining on your jumper has lots of different wavelengths in it, and your jumper is absorbing some of them and reflecting others back to Adam's eyes.

And then in Adam's eyes, there are light sensors called cones, and they absorb different wavelengths of light differently from each other.

So the light that's bouncing off your jumper has a high concentration of long wavelengths in it, and that's why it looks pretty pink.

It's also got a lot of light coming from it.

It's quite a bright jumper.

So in Adam's eyes, these light sensors called cones sample that light and they detect how much is in the long wavelength part of the spectrum, that's what we would normally call the reddish part of the spectrum, and how much is in the middle and how much is in the short wavelength part of the spectrum, and they send a signal about what kind of light they've collected up to the brain.

Gabby, how does this relate to the primary colours?

So we have three types of cones in the retina.

One is sensitive to short wavelength light.

Sometimes people call them blue cones.

We have the middle wavelength sensitive cones or M cones and the long wavelength sensitive cones.

And they all have different kinds of opsins in their photoreceptors that make them sensitive to slightly different ranges of light.

And what's an opsin?

So an opsin is the protein part of the photopigment molecule.

So when a photon of light is absorbed, that basically triggers a switch in the molecule.

So light energy is then transformed into a different kind of energy, which is electrical signals that are passed onto the brain.

Anya, if there are these three cones, I mean, I am going to call them red, blue, and green.

But if there are these three primary cones,

is it a bit like the way that, I don't know, computer monitors work, where they have the three colours and then they blend together and you see all the colours of the rainbow?

Exactly like that.

So, from the three

RGB values of a square that you put on your screen when you're making a PowerPoint slide, you can generate almost any colour.

In fact, you can generate 16 million colours from those three different varying values of RGBs.

Because of the fact, as Gabby said, we've got only three light sensors in the eye.

So fundamentally, we always decompose light signals into three numbers.

Okay, but the retina is a really complex piece of tissue, and it looks like a bit of a sort of an extension of the brain.

Anyway, what happens after that light has triggered an electrical response?

Where does the signal actually go then?

Exactly right.

I mean, the retina is like a mini-brain in and of itself.

It is, in fact, part of the brain.

It develops from the same neural tissue as the brain.

And the photoreceptors are just the first stage.

They send their signals to other layers of cells.

And ultimately, the final layer of processing is the ganglion cell layer, where the differences between the cone signals are taken.

So it turns out that what we're calling the red and the green cone types are very similar in their sensitivities.

So they collect very similar amounts of light.

So what's actually interesting is the difference between them, because that's where all the important information is.

So the amount of redness versus greenness in the light, rather than just the absolute amount of red or the absolute amount of green.

I don't think I'd quite clocked that before.

I think I sort of thought that it was like, you know, when you sometimes see a photograph and then they print the red bit first and then they print the blue bit and then they print the yellow bit on top and then when you put them together, maybe with a touch of black, suddenly the image sparks into full glorious technicolour.

I think I had sort of imagined that that was what it was like in the brain, that you have like the red bit going in, then the blue bit going in and the green bit going in, and you just add them all up and then that's how you see in colour.

But what you're saying is that actually there's much more complicated processes.

Absolutely, absolutely.

Because instead of just recording the amount of blueness, greenness, or redness, the whole system is working out the difference between the amount of redness and greenness, and then the difference between the amount of blueness and yellowness, yellowness being the sum of the redness and greenness, because that's where all the important information is.

It's beautiful.

It's the most magnificent system ever evolved.

Because what happens is you get a bunch of photons hitting the back of your eye, bouncing off Hannah's jumper, and instantaneously I can describe it as being salmon pink.

It also goes wrong, though, doesn't it?

I mean, this stuff is quite easy to trick.

It is very easy to trick.

And this fundamental nature of redness versus greenness, blueness versus yellowness, we call it colour opponency, is the reason why you can see really, really dramatic visual illusions.

And you've got a demonstration of this.

I've got a demonstration of coloured after images.

Okay, so we've got on screen now, you're showing us an image of Dunstanborough Castle.

Oh, you know Dunstanborough Castle do you?

No.

It's very pretty.

It's the most beautiful ruin.

It's up on the coast of Northumberland and what you're seeing here is just a black and white image of Dunstanborough Castle.

And now we're going to flip to another image which you'll see is quite weirdly you'd say that's pretty weirdly coloured eh?

It looks a bit like

a homemade 1970s synth album.

Yes.

Or an effect from a Doctor Who episode.

Yes.

To show an alien planet.

right.

It's a bit psychedelic.

The grass on this is a sort of, well, blues and purples and oranges, and the sky is like, mmm, a muddy colour.

Now I need you to stare at that black dot in the center of the image for about 15 seconds.

And what we're doing here is we're trying to rebalance the red, green, and the blue-yellow colour opponent channels.

So in different parts of your eye, those channels are being rebalanced differently.

Now I need you to keep staring at it, which is why I'm talking, talking, talking.

And now we're going to just flip the image to the black and white image.

Oh, my Lord.

Wow, that's amazing.

That was incredible.

Now, just keep looking.

It will slowly fade away, but what you should see is a real colour version of Dunstanborough Castle.

The grass has gone green, the sky has gone blue.

That's absolutely blue.

The water has gone bluish.

And actually, of course, what you're looking at is the original black and white image.

And so this would not be possible if it were not for the fact that our brain is looking for the differences in colour rather than the total amount of colour overall.

Yes, yes, roughly speaking, what we've done is

we've over-stimulated the reddish side in one part of your retina so that then when it sees grey, it thinks it's green.

And likewise where we showed a lot of blue on your retina, when we then show a grayish colour, the yellow will be much stronger in that blue-yellow colour opponent channel.

Okay, this is wickedly complex, but let me do a simple upsum here.

We have three types of cones which have molecules in them called opsins, and those opsins are tuned to pick up specific wavelengths of light.

A-STAR, GCSE biology.

Thank you very much.

Now, as ever in biology, we can learn about how things work when they are broken.

So, Gabby, let's talk about colourblindness.

Well, normally we talk about red-green colourblindness, which is the sex-linked colourblindness that mainly affects men in the population.

So it's one in 12 men, or one in 12 boys, who are actually colour deficient.

We have very few women who are colour deficient, it's less than half a percent.

Is that the only type of colourblindness?

Are there other types rather than just red and green?

Yes, there are other types of colourblindness, but they are not very common.

So you can acquire a colour vision deficiency, for instance, if you take toxic substances, or even if you're smoking, you can detect a loss

in your blue discrimination.

Far rarer are monochromacies or achromatopsias, which means that somebody is truly colorblind.

Sees very rare.

They see in black and white, and that's very rare.

It's one in 30,000 usually.

I think I know someone who does that.

My brother-in-law's dad

only sees in black and white, and as a result, his wife has taken extreme liberties with the decoration of their house.

It was very careful.

He's got no idea.

Hot pink bedroom, everything.

Let's just talk about the reason why it affects boys more than girls.

Yeah, so we have a red, green, a red gene and a green gene and they sit on the X chromosome or sex chromosome.

And because men or boys only have one X chromosome, when they have something faulty on their X chromosome in that region, they basically express that in terms of colourblindness.

Whereas a woman who has two X chromosomes can always compensate for having a faulty gene on one X chromosome by having the normal ones on the other.

And it is remarkably common.

I mean what were the numbers you just said?

It's one in 12.

Yeah, it's 8% of men or 1 in 12.

So there's at least one in every classroom, but only one in 200 women.

Does everyone know that they're colourblind?

I'm just thinking of it.

One in every classroom is a lot.

Is it obvious that you're colourblind?

So not that obvious.

If you are severely colourblind and you are missing a photopigment,

that tends to get picked up by the parents.

So when the kids are kind of dressing in a funny way, they're putting different coloured socks on.

So a person who's missing a photopigment is then picked up.

at home or at school and they tend to know it.

The problem is that the majority of colour deficient boys, they vary a lot.

So they have three types of cone, but either the red or the green cone can be shifted in its spectral sensitivity, so they get very close and they can't discriminate between these colours very well.

This came up recently in

the Six Nations in the International Rugby.

The BBC reported on some people complaining, men complaining,

unbelievable, men would complain about anything.

Men complaining that they couldn't distinguish between the shirts in the island versus Wales game.

Well, because one's red, one's green.

Yeah, yeah.

And actually, and if you look, here's a picture of what they look like.

It's been decolourised.

So this is if you were to have

red, green colourblindness, you've doctored the image to look like that.

And actually, I mean, the shade of it is identical.

It's identical.

I mean, the way to distinguish between the Irish and the Welsh is because the Irish one.

That's a...

They're the ones with a ball.

They're the ones with a ball.

Oh, we're going to get so many complaints about that.

One thing, though, I'm just thinking back to what you said about how it's not always picked up immediately.

I find that really extraordinary that it's possible that you could have such a different perception of the world around you to the person you were sitting next to and yet never know it.

I mean, that's quite a mind-boggling thing to imagine, Cabi.

It is, and it's actually one of the biggest discussions or one of the most common discussions around a dinner table: it's the red that you see the same as the red that I see.

And of course, our language doesn't help because we've been told that a strawberry looks red, and you've coded most of the colours that you see with with labels as well.

So unless it's put to a test, then you know it's it's very it's very difficult to know what we actually see because colour is in the in in the eye of the beholder.

So if you have different types of observer, a colourblind person or a normal person, they would construct this colour very differently from one another.

And it's it's not necessarily by talking to one another that they notice a difference because as I said they they probably use the same labels.

Actually in the original question, it was about a teacher who was colourblind but only to red, green, and pink, and was puzzled as to why it's only those colours.

So, the red and green, as you that's the one you've been describing, but but pink, where does that come in?

Yeah, so pink is really just a desaturated red, which means that it's a red that has a lot of white in.

But in general, red-green colour deficiency means that people are more likely to confuse a whole range of shades around red and green, not just red and green themselves.

Okay, well, we're being a little bit human-centric in all of these discussions here because although most of us see in three primary colours, we have three different types of opsins in our cones, but that's not the case for most animals, right?

And this was one of the questions, Adam.

Yeah, that's right.

So, I mean, it's hugely variable.

Cats have very few cones and they don't really see red very well.

We think that cats sort of see in a sort of bluey, violet, yellowy green, don't really see red at all.

What would the cat think if it watched Island Wales rugby?

Utter indifference.

No changes there then to the cat engaging with anything else around it.

Exactly.

Interesting rugby at all.

Do you know that reindeer can see in ultraviolet light?

Do you know this?

It's pretty extraordinary.

So if you think about the landscape that a reindeer exists in, if you were looking at it as a human, it's completely white, right?

Like very difficult to distinguish anything.

But if you put put UV goggles on, suddenly you would be able to see a few markers in the snow, particularly reindeer urine, which actually under UV light appears black, and lichen, which is a very important food source for reindeer.

So they've essentially developed this extraordinary ability to kind of cut through all the white and find its way to other reindeer and food sources.

Evolution is much cleverer than us.

Well, lots of animals have lots of different ranges which are evolved evolved for their environments.

The king of all of these though, the kings and queens of vision really is the mantis shrimp.

16 different types of opson can see in not just the ultraviolet spectrum but also can see polarized light.

We don't really know why.

It lives about 1,200 meters underneath the sea, which is really black.

How many did you say?

16.

Butterflies have about 11 or 12.

So you imagine that.

Well, it's impossible to imagine it because it's like Dorothy in the Wizard of Oz stepping out of the black and white world into the technicolour of Oz.

We can't even conceive of how that's possible because we simply don't have the hardware.

I don't know whether the Mantis Shrimp can even conceive of what he's seeing, though.

I would argue with you that he might just be sort of seeing differences between wavelengths in different bands, but is he really conceiving colours the way we do?

I don't know that he's got the brain power for it.

Well, until we learn to talk to Mantis Shrimp, that one will remain a mystery, I I think.

Well look, I mean we're I could talk about this all night and day but we're only just scraping the surface of the mechanics of understanding how vision actually works.

So one of the questions that came up Anya was say for example we were shining a red light on a piece of paper, a white piece of paper.

The light bouncing off the white piece of paper is red because the source light is red, but we still know that that piece of paper is white.

How does that work?

You have hit on what I think is the fundamental phenomenon at the heart of the way we see colors.

It's called color constancy.

Yes.

So why do we see colours?

We construct colours in our brains and we construct them so that we can discern things about those objects that we care about.

We want to know what materials they're made from, whether we should eat them, whether they're poisonous, whether they're delicious.

And so we use color as a way to get a handle on those those important material properties.

But we need colour constancy to do that, because if the colours we saw continually changed, as the light shining on them changed, then we couldn't use colour in that way.

It wouldn't tell us anything meaningful about the objects.

So we assume that a strawberry is going to be red.

And so even if the light is suddenly very blue, in our minds, we know the strawberry is going to be red, and then we expect it to be, and that's what we see.

Well, a lot of it happens first in the eye and at the stages between the eye and the brain where we do this thing we talked about before, adaptation.

We sort of filter out the blueness of the light if it's blue light shining on the strawberry.

So we can recover the fact that strawberries are reflecting more reddish light than other objects around them.

Annie, do you remember that whole kerfuffle about the dress a few years ago?

Oh, do I remember that?

It was the moment when suddenly vision scientists who studied colour became important.

So this was a photograph photograph that was taken of a blue and black dress,

but in the photograph, to some people, it looked as though it was white and gold.

Now, Adam,

I asked you about this earlier, and you, I think, are the only person in Britain who didn't see this photograph.

I think I rather, I remember it happening, and I remember also rather stubbornly deciding that I wasn't going to participate in this ridiculous thing.

So, I've only seen this image, I promise you, for the first time today.

I've got it up on my screen right now.

What colour is it now?

It's blue and black.

Is it?

But you saw it as white and gold earlier.

It's a different dress.

It's not.

It's obviously a different dress.

That's not the same dress.

What colour is it to you, Gabby?

Black and blue.

Definitely always, never change.

Really?

How about you?

And the first time I saw it, I said white and gold.

And I was utterly confident in what I saw.

As were the other half of the population who saw it as white and gold.

It literally is about a 50-50 split.

Looking at the same image in the same viewing conditions, on the same screen, smartphone,

how does that work?

I find this deeply upsetting.

So we, when we construct colors, do that inferential thing totally unconsciously and filter out what we perceive to be the light shining on the object so we can get at what the object is really reflecting.

But everybody's brain does that differently.

So that image could be made from a black and blue dress under yellowish light, or it could be made from a white and gold dress under bluish light.

And different people totally unconsciously make a different inference.

And if their brains unconsciously filter out bluish light, they see the dress as white and gold.

If their brains unconsciously filter out yellowish light, they see it as blue and black.

Are you recognizing that this is my upset face?

Yeah.

Right now?

I am.

Because I think that it feels like there is an objective reality out there, and our job as scientists is trying to understand objective reality, and there is a wavelength of light bouncing off that clearly black and blue.

Adam, I have a surprise for you because I want to bring us back down to reality.

Oh, I don't know whether I like surprises like this.

Oh my god, it's the actual dress.

Is that the dress?

Voila, this is the dress.

It's clearly very clearly blue and black.

It's blue and black!

Well, I would say it's not blue and black, because blue and black, that's in our heads.

All I can say is that under this kind of lighting, everybody would agree it's blue and black.

But I can take this same dress, which we did up in Newcastle, with this real dress, putting it on a mannequin, and we shone different lights on it, a mixture of yellowish lights and bluish lights, and people came in, and one person would say white and gold, and the other person would say blue and black.

Well, actually, that does bring us on quite nicely to our last question that James Martin asked.

He said, are colours real?

Are they just perceived?

Now, the dress, I think, is one angle on this, but we are going to have to get a lot more philosophical to try and answer this one.

So, strap in.

Yes.

So, we accept that the wavelengths of light are real.

And the way that we scoop up those photons, that is also a physical mechanism.

But then it all has to be processed.

As we've talked about, it goes through different types of cells and the retina and then it goes into the dark recesses of our skulls and there's all sorts of influences there which change our perception the purpose of this is that the brain is interpreting light and turning it into something that we can understand yeah because if you think about the rainbow right richard of york gave battle in vain there are some colours that you can definitely see that definitely are not in the rainbow to explain what's going on here we called on philosopher of neuroscience from the university of Edinburgh, Dr.

Majrita Chirimuta.

Brown is a particularly good example of a colour that isn't there in the spectrum.

There's no brown in the rainbow at all.

When people first start thinking about the physics of light and colour, they often get into this idea that, well, what colours are are just wavelengths of light.

But if you look carefully at the colours of the rainbow or the light spectrum, you don't see plenty of the colours that we encounter in everyday life.

So if you you look at the wavelengths of light that get reflected from a brown object, they'll be in the yellows and orange range, but it's almost like it's a darker orange than you could ever have as purely a light.

And the thing about brown is also that you can't have a brown light.

Brown is only there as a colour of a surface of an object that has to be seen in the context of other objects.

So it's really curious.

It's like it's a relational colour.

You need other objects around the object in order for it to appear brown.

Right, so colour perception then depends on the particular way that we interpret light, and that depends on some quirks of how we put together and what cones we happen to have, as well as how our brains process and combine neural signals.

So

where does that leave us?

Are there any colours that are real or are they all just made up?

I think the best way to think about colour is that it is both real and at least in part something that is generated by our minds.

Without all of this elaborate stuff happening in our visual system and in our brains, without that I don't think that any objects would be endowed with colour.

But at the same time, I don't think that means that colours are not real because I think there can be a kind of reality which is also dependent on how our own minds interpret the world.

So if you like, we should think about colours as they're because of a relationship which is there between the objects we perceive and our visual systems and our minds.

Anya, this strikes me as a

language problem more than anything.

So, James's question relies on what the word real means.

Things that happen in our head are still real.

Yes, in fact, the only reality any of us has is what's going on inside our heads.

Yeah, but is your red my red?

I have no idea, but I know what my red is,

and I think I'd get really confused if I had to keep jumping around inside other people's heads to work out whether their red was the same as mine.

Well, on that note, thank you very much to our guests, Annie Hilbert and Gabby Jordan.

Thank you.

So, Dr.

Brotherford, when it comes to the many questions of how we see colours, can we say case solved?

Yes, we can, Dr.

Fry.

Light comes in waves, and we we have molecules in our cones, which are photoreceptors at the back of our eyes, that are tuned to pick up specific wavelengths.

And those are the primary colours.

Some people don't have a full set of cones, though, and they might not be able to see as many colours.

But some animals, like the mantis shrimp, have loads more receptors for whole other dimensions of light, such as ultraviolet and even polarised light.

But we don't really understand how they actually use them.

We do know, though, that all colour perception happens inside our heads.

And that doesn't mean that it's not real.

Okay there was colour vision.

We covered the whole of colour vision there.

I mean I think you know that that this actually was my area of research.

I yes indeed you have mentioned it once or twice.

Once or twice before.

Much time you spent looking into eyes that were not your own.

Well that is true.

But I do absolutely love it.

It is so fascinating though, isn't it?

Yeah, if I'm really honest with you, I think I'm more confused now than i was at the beginning

is this what it's like to be you yes welcome to my world you're getting an insight into my brain i so when we we we were talking to anya about the how the the retina is a sort of offshoot of the brain it develops from the same tissue as the brain it has these layers which are a bit like the um the the external structure of the brain itself.

Now, just to give our listeners an indication of how specific PhDs actually are, you've got rods and cones in the outer layer, which is what we were talking about, and then they wire up to what's known as the inner nuclear layer.

And that consists of two different types of cells, which are called bipolar cells and horizontal cells.

And they wire to each other, but also to the different types of ganglion cells, of which I think from memory there are 11 different types.

I think it's 37 now, Adam.

Anya's still in the studio and she's just revealed herself.

Is it really 37?

Something like that.

Okay, well, I worked on one type of bipolar cell that is in the middle layer.

Good.

For how many years?

Three.

Good.

Good.

I had a special mouse.

Yeah.

I didn't grow them at all.

Forging forwards the path of human knowledge.

Yes.

One tiny cell at a time.

Yes.

If you want to know about bipolar cells in the human and mouse retina,

I've forgotten that.

Danya's probably got a much better idea.

Anyway, it is the final show in the series.

Uh, so we've got to do some uh meeting notes, any other business, including two apologies.

There are two apologies.

Um, some people were very, very upset with us about Harold Bluetooth.

Yes.

Um, not that Harold Bluetooth is, uh, was mentioned, or even that there was a man called Harold Bluetooth, which still remains to me one of the best names of all time.

Yes, so

a lot of people wrote in to complain about something that I said.

What was it that you said?

I said that

I said that people who named Bluetooth Bluetooth just liked Danish folklore.

Sure.

But actually, as Jim Bolton wrote in,

Jim Bolton's a naming consultant, in fact.

And he's a trustee of the Centre for Computing History at Cambridge.

Important man.

Yes.

He says, as such, I thoroughly enjoyed the weird waves of Wi-Fi.

That was the Wi-Fi episode.

However, I'd like to challenge Adam's assertion that Bluetooth is just a cool name and has nothing to do with technology.

Just as Harold Bluetooth Gormason,

that's the Bluetooth guy, united the warring Viking tribes, Bluetooth, united wireless communications protocols.

Right.

I am a nerd, yeah.

I am an absolute cast iron, died in the wall, nerd.

And that one is one step too far for me.

Too far, too nerdy even from for Hannah.

Shall I tell you who the other apologies to?

Yes.

It's Donny Osmond.

Oh, what did we get wrong with Donny Osmond?

Okay, so we said that Donny Osmond was one of those people whose inside were flipped around.

This is in our episode about symmetry.

Situs invertis.

Exactly.

So where your heart is on the right-hand side of your body, your appendix is on the left-hand side, and so on.

Now, we

found this fact in numerous BBC articles and so on.

However,

in

bad style, we did not go to the original source.

We did not.

Sometimes we throw you in facts and we don't go to the original source.

And this is one of those cases.

And we have been told that

Donny Osmond doesn't have sorices in verses.

Donnie Osmond has denied this, but

we couldn't find any evidence that he denied it.

However, we did find one quite creepy clip of Donny Osmond on a chat show in approximately 1990 where he show, well, it's sort of there's a bit of a tussle with him and

the female host where she goes, show them your appendix scar.

He goes, no, I can't.

Okay, I will.

He's quite shredded as well, isn't he?

Yes.

Well, listen, to the the lawyers, to Donny Osmond lawyers, what we said was not, had no malice

intended in it, and we apologise for suggesting that his organs are the wrong way round.

And let that be the end of this.

Now it's time for Curio of the week.

Now it's a visual one for Curio of the Week.

Back in series 14, you will remember that we did a two-parter in which I attempted to scare the bejesus out of Macaulay

by making her watch horror films against her will.

She really didn't do it at all, if you remember.

Anyway, Chris from Manchester has designed the movie posters.

Not just the movie posters, the best possible movie poster you can imagine, because it is the outside of a very Halloween-esque cinema.

On the left-hand side is a photograph of Adam in the poster bit.

On the right-hand side is a photograph of me.

And what they have is as though we are appearing to decide what to watch in the movie.

It's called A Frightful Scare Part One.

And where the names of the titles that would be showing within the various theatres would normally be.

It has the caveats that I added.

The criteria when I was trying to to select a film, which included no knives, no core, definitely no chainsaws.

Yeah.

Poltergeist, no.

The shiny.

Days later, no.

The shiny, no.

Godzilla, no.

I mean, basically, it was nothing at all.

Yeah.

Anyway.

Well, you still managed.

It was still pretty scary.

Anyway, Chris from Manchester, brilliant.

We'll stick them up on the gallery, on the website, along with all the pictures from the show, including some of the visual illusions that we talked about in today's episode.

And so that is it for us for another series of Curious Cases of Brotherford and Friar.

We will join you again soon, sometime in the future.

Sometime in the future.

Death by Conspiracy, a new podcast from BBC Radio 4.

Gary Matthews was an artist and photographer, a familiar sight on the streets of his hometown in Shropshire.

But in the last few years, he was drawn to conspiracies.

And when the pandemic hit, Gary, who was suspicious of experts, ignored the rules.

When he died of COVID-19, his distraught family and friends were left searching for answers.

I'm Marianna Spring, the BBC's specialist disinformation reporter, and I've been investigating what happened to Gary by delving into the conspiracy underbelly of the picturesque town of Shrewsbury.

From BBC Radio 4, Death by Conspiracy, a new 10-part podcast series.

Subscribe now on BBC Sounds.

A happy place comes in many colors.

Whatever your color, bring happiness home with CertaPro Painters.

Get started today at Certapro.com.

Each Certipro Painters business is independently owned and operated.

Contractor license and registration information is available at Certapro.com.