Penrose Unilluminable Room Is Impossible To Light

[@SteveMould]

Action Lab's video is here: kzbin.info/www/bejne/n5-wmpuEhc-YrK8 The sponsor is KiwiCo: Get 30% off ANY crate: kiwico.com/stevemould30

[@BackYardScience2000]

​@Don't Read My Profile Photo ok., we won't.

[@khalilahd.]

🙏🏽🙏🏽

[@local-admin]

Too exited for these back to back!

[@BackYardScience2000]

I knew I saw this video topic elsewhere recently.

[@sumo_asl]

Yoooo

[@zakaryreilly]

Nice to see a real life Penrose "room" rather than a simulation. Love how you always make tangible demonstrations rather than just explaining theory

[@zoinksxscooby]

I agree his 2d constructs are beneficial for grasping the ideas he is trying to explain. Another reason I love learning from this guy as he can visualize an idea like I haven't seen before.

[@fangzhang9376]

@weeblebrox That someone has done something similar first doesn't detract from his work, and both are great channels.

[@WanderTheNomad]

@@fangzhang9376 OP didn't even say anything about Steve being the first to do it, so I'm not sure what you and weeblebrox are on about

[@Ginger_Starz]

No action lab is better

[@fantom9435]

That is the best Part for me too, It really helps a Lot to really grasp stuff

[@TheActionLab]

Ha ha, great minds think alike. Great video!

[@ooghaboogha4362]

Indeed

[@ooghaboogha4362]

നിങ്ങളുടെ വീഡിയോസ് ഞാൻ കാണാറുണ്ട്

[@ooghaboogha4362]

ഞാൻ ഒരു ഫാൻ ആണ്

[@ooghaboogha4362]

സ്വയം പുകതൽ ലോല

[@OfficialSamuelC]

Aha

[@Mikaci_the_Grand_Duke]

The weirdest thing is to imagine you sitting in a dark spot of that room looking towards an illuminated wall, but still seeing nothing at all but darkness, despite that the wall is being illuminated. Hard to imagine, but don't forget those walls are mirrors, and they reflect light only in specific directions, they don't spread it randomly. However it's really hard to accept this thought. Maybe it's worth putting a camera into a bigger model, so we could see, how does it feel and looks like to be in such a room.

[@RM_VFX]

I think in such a room, if the walls were perfect mirrors with no smudges, you wouldn't see an illuminated surface, only a reflection of a point light source. Therefore, if you were in one of the unilluminable alcoves, you would see nothing but darkness in any direction. I think this would also require a perfectly black floor and ceiling, since those would reflect light as well.

[@Mikaci_the_Grand_Duke]

@@RM_VFX Exactly. However I would like to extend the first part of your answer with some thoughts. Because the point of light is many times reflected there could be a point in the room, where you can only see one light source, but at most places you would see plenty of them shining from different directions, or even horizontal light stripes, if the reflections are so close, so they virtually merge into a stipe.

[@RM_VFX]

@@Mikaci_the_Grand_Duke Right, on a concave surface that would happen in places. The point is, if you're in an unilluminated spot, you wouldn't see any reflection at all, because by definition, no light is hitting that point, and nothing to hit your retinas either.

[@james-m-8285]

You could look at a person standing against said wall and all you’d see is them, like a reverse silhouette

[@animeloveer97]

@@RM_VFX so by this logic youd also blinded in the lighted places from all the reflection?

[@frosty3579]

I actually like when multiple creators cover the same topic. It gives different points of view and explanations so the subject is covered more broadly.

[@NukeMarine]

I'd love to experience what a live size version of the room would do with sound. Like, you have dead spots but how hard would it be to locate sound that you can hear.

[@Kenabukanyo]

It's called backrooms, but yeah. I'd wanna know too :))

[@siyaryamin4904]

Not really much, sound travels around corners

[@a.static.kaleidoscope]

sounds a wave

[@iamwisdomsky]

hate to break it to you but unlike light, solids are conductors of sound. so what will happen is sound will just go through the wall.

[@avananana]

You must be fun at parties.

[@alexfm4645]

A part of me cried a little, when he drew the ellipse @2:49 and just before he finishes the knot disrupts the shape.😅I was totally mesmerized by the smoothness of the movement and then was suddenly reminded of the little problems of practical setups

[@jo54763]

You might be able to wrap the knotted part of the string around the marker/pen, as long as the diameter of the pen stays constant and the string doesn't present too much friction. Trying to think of reasons why it might not work and I can't think of any.

[@TyphonMar]

One could use an elastic

[@zackhenderson2392]

@@TyphonMar Yeah but then the elastic would stretch, so you'd have to keep it stretched the same all the way around.

[@emmfranklin]

Now that made me think . can we really invent a thread that has no knot and is circular.

[@Muonium1]

This is why we use a (cross-sectionally) ellipse shaped reflective space for the pumping cavity in solid state lasers. The heart of a sold state laser is a crystal rod doped usually with neodymium erbium or ytterbium and the atoms in the rod are pumped by absorbing light emitted from a high intensity xenon/krypton flashlamp also in the shape of a rod situated at the second focal point opposite the laser rod inside the ellipse. Almost all the light from the lamp therefore goes into the laser rod.

[@SteveMould]

Cool!

[@Muonium1]

@@SteveMould Additionally, I cannot help but notice the Penrose room (minus the reentrant mushroom intrusions) looks remarkably similar to our "rugby" hohlraums used for indirect drive laser fusion. Here, we are trying to convert ultraintense (terawatt) UV laser light pulses into x-rays by shining them onto the inner wall of a gold or depleted uranium coated hohlraum where the deuterium-tritium fusion capsule lies at the center of it, because the soft x-rays are absorbed much more uniformly by the fusion target than if it were irradiated directly by the lasers themselves. But the laser light entering the hohlraum must not be allowed to impinge directly onto the target itself, and I suppose - without looking up the papers, this must be one of the reasons for the rugby shaped (as opposed to simple cylindrically shaped) hohlraums that have appeared fairly recently in our experiments.

[@XxpurexrussianxX]

@@Muonium1 what field exactly do you work/research in?

[@Muonium1]

@@XxpurexrussianxX laser driven inertial confinement fusion optics engineer

[@goose300183]

Fascinating stuff here! You may be able to answer this, if you want to of course. Ever since I heard of them, I don't understand how a quantum cascade laser can be tuned to a different wavelength. I heard it at a conference once; someone was doing spectroscopy with QCLs, and he was able to change the emitted wavelength seemingly quite easily. That was just a big "did not compute" for me! Is it a built-in property of QCLs?

[@pyglik2296]

Roger Penrose must be an amazing guy. He solved a mathematical problem, and instead of publishing the result in a paper, he turned it into a Christmas puzzle in a magazine.

[@murunbuchstanzangur]

Its impossible to not recognise the guys genius, but i hear he is a bit of an arsehole in real life. I know he has sued people for using penrose tiling patterns in their products. But i guess professors arent super well paid and its one of the few things that he can monetize. So maybe its just rumours.

[@briansammond7801]

If you think he's amazing because of this puzzle, you should look into the rest of his work. He was Stephen Hawking's collaborator on Black Hole Singularity Theory, and won the Nobel Prize in physics in 2020 and the Wolf prize much earlier. He invented non-periodic tiles for tiling the plane, which were important in quasi-crystal theory. He delved deeply into quantum mechanics, mathematics, computational theory, artificial intelligence, mind theory, consciousness (and more) in several popular (and controversial) works, such as "The Emperor's New Mind" and its sequels.

[@michaelkaliski7651]

Roger Penrose was the author of one of my school maths textbooks and that was 52 years ago!

[@thejimmymeister]

I second the suggestion to look into his other work. I first became interested in him through philosophy of mind, but he has done amazing things in many fields. There are lots of very good videos of him giving lectures which are very accessible without being superficial, too-an accomplishment in itself, especially with the very high level mathematics, physics, etc. he studies. Between the breadth of his accomplishments and interests and his ability to explain things clearly and with some pleasant personality, he reminds me a lot of Bertrand Russell. In my opinion, he's one of the greatest minds in history. Coincidentally, I just learned today that he, along with his father, created the continuous staircase that M.C. Escher made famous. It seems that whatever you've learned about him, there's still another accomplishment of his to find out about.

[@pyglik2296]

Reading through his Wikipedia page: "Oh, it's the same guy as the Penrose triangle, cool." "And the Penrose tiling as well, interesting." "Moore-Penrose inverse of a matrix, never heard of it." "Penrose-Hawking singularity theorems, what?!" "Penrose process, something about black holes..." "Penrose invented the twistor theory which maps geometric objects in Minkowski space into the 4-dimensional complex space with the metric signature (2,2)... I'll pretend I understood that..." "Penrose diagrams, how many thing were named after him?!" "Penrose interpretation about quantum mechanics and general relativity..." "The whole chapter on consciousness and of course Penrose-Lucas argument." "And he got a Nobel Prize "for the discovery that black hole formation is a robust prediction of the general theory of relativity" ." Yeah, he is an amazing guy.

[@RandoManFPV]

It would be really cool to have a full size completely legit room just like this but with multiple lights and switches wired so that any time you flipped a switch only one light would be illuminated. I could see this having a unique use in a museum or something to literally bring to light certain areas of a room for an interactive experience

[@nthgth]

I agree. Could be useful in a first-person video game too, or maybe one of those "backrooms" type videos.

[@yuki97kira]

A horror game idea!

[@caltheuntitled8021]

If you made all the walls mirrors, you could demonstrate it in a much simpler way by placing some object in each of the pockets. No matter where you stand, you can’t see all 4.

[@rolirolster]

Great idea!

[@skittleseer1]

That explains the lighting issue with my Penrose bedroom. And I thought it would be fun with all those mirrors!

[@AreThereGhostsOnMars]

I feel like this room would be a perfect level in a horror game where you have a flashlight and everything is dark.

[@GaleGrim]

Hmmm, maybe instead the horror is a "light source" if you aren't in the unilluminiated spaces of the room when it enters it's "active phase" it will find you based on if your are where it's light hits and [redacted], Maybe you have to carry it with you in it's dormant state on a timer to an objective avoiding things things that might activate it early and then scurry to safety before it turns on. Maybe indicate a path the horror will follow and you have to move quietly and quickly to areas where it's light won't hit you and [redacted] while avoiding other hazzards? Alternitvely, the horror will move towards you if it's hit by the light from t your flashlight, the more directly the light hits it the faster it finds you, but there is something else that lurks in the dark that needs to be staved off with your flashlight as well or [redacted]? There is a lot of room for playing with light, detection, effects, and darkness in this room.

[@kazukihashimoto183]

how is that related?... wtf?.... you can see with a flash light in this room normaly.... just that there would be parts in the room where light wouldnt bounce that you wouldnt have bin able to see anyway from your perspective....... your comment makes 0 sense.... you either didnt watch the video or you didnt understand any of it... tho 53 other ppl didnt understand this as well or just liked your comment coz youre a woman.

[@GaleGrim]

@@kazukihashimoto183 Sure cause 54 people like the comment for some reason, but you don't so THEY must be wrong/disingenuous and thus "simping". Get a fucking grip dear. This room has interesting effects on the dispersal and redirection of light and other particles, meaning parts of it are dark at all times when only one light source is present. An environment where darkness is always present is almost perfect for a Horror game. It's IN THE NAME " *Unilluminable* Room Is Impossible To Light". It's the whole premise of the video that it isn't the same a every other room when it comes to light sources, look at 0:25 if you don't believe me. Just because you don't understand something doesn't mean it makes no sense. They were relating it to a thing they are familiar with and how the rooms properties might be used in that thing they like. It's not rocket science. Also you have "Joined May 23, 2022" on your profile, which means you just joined KZbin yesterday. I don't wanna hear a word about other peoples comments being bad from someone who just logged on for the first time yesterday and knows jack shit about the platform. Especially not from a sexist, misogynist, douche bag like yourself. Who assumes the only reason someone would agree with a woman who they think is wrong on the internet is cause they are pretty.

[@kazukihashimoto183]

@@GaleGrim typical female over reaction to a logical argument , 0 logic or rationality in your reply only feelings idk why youre acting all mad and trying to lecture me but it is pointless to say anything to you anyway so Yaws queen youre right.

[@AreThereGhostsOnMars]

@@kazukihashimoto183 why are you being rude for no reason? The point is that there will always be dark spots where the horrors can hide. It’s just an idea that I thought was cool. It doesn’t have to be a perfectly fleshed out game mechanic that makes perfect sense, it’s just brainstorming.

[@R2Bl3nd]

It's crazy that both you and action lab had this same idea in such a short time span. It's like the invention of calculus

[@palleppalsson]

Yeah me and Newton had the exact same idea.

[@R2Bl3nd]

@@palleppalsson Leibniz? You're still alive? 😂

[@wild-radio7373]

I'm right there with you!♡

[@gordonspond]

Noticed that too... Action lab did a really nice video on it.

[@gljames24]

It's cuz Nils Berglund's simulation was making the rounds on social media and they both wanted to cover the topic.

[@khalilahd.]

Science KZbin has to be the best niche out there. I never know what I’m going to learn about each upload yet I’m never disappointed and this video is no different 💛🙏🏽

[@MaskedDeath_]

I like Science KZbin but for the opposite reason. I usually know exactly what I'm going to learn, and the content creators always deliver. No clickbaits etc., just exactly what I wanted to see.

[@supergsx]

Don't stop yourself just because ActionLab did it! I would re-watch the same topic taught by a different teacher. You guys are both great!

[@frankroquemore4946]

I’ve always wondered what it would be like inside that room. Like imagine walking around in the main open space of the room and if you cross an invisible line on the floor then everything suddenly goes pitch black

[@rafasilva1265]

Not really how it would work, the line would be visible because no light would come from there. It would just look like a normal shadow. If you stood inside that shadow then you wouldn't see much light but then again, light bends around corners, and you would see a little bit of it.

[@andrewchapman2039]

This is exactly the sort of detailed and nerdy breakdown of the room I was hungry for after that Action Lab video, so thanks so much for still publishing it!

[@NoTimeLeft_]

3:00 yes yes complete the elipse.. here it comes...... Arrrggghhhh Steve!! How could you!?!

[@SteveMould]

I'm so sorry

[@christophergeorgia9670]

Lol

[@NeatNit]

In the excerpt at 7:53 it says: "The precise shape of the lower curve is unimportant but [...] **it must also be smooth and fit smoothly on the elliptical arc at P and S.**" The mushroom shape isn't smooth though. A smooth curve, for those who don't know, is basically a curve that doesn't have any corners. The more formal definition is that the derivative of the curve must be continuous, but that's not important. I wonder why Penrose thought the curve has to be smooth. It clearly doesn't - it doesn't even have to fit smoothly on the elliptical arc, best I can tell. However, maybe the smoothness gives it more properties that a non-smooth shape (e.g. the "canonical" mushroom shape, which has corners) does not? Maybe a smooth shape will even be able to contain *waves* in the desired region, rather than just rays/particles?

[@SteveMould]

Yeah, I wondered that too

[@eekee6034]

Is diffraction more noticeable from sharp edges? I think it is, but I'm not feeling very well and can't think straight right now.

[@animeloveer97]

i also had the same thought lol but i dont quite understand why but your explanation helped

[@Flyzguy]

I wonder if the way he was modeling it at the time required smoothness for his proof to work?

[@NeatNit]

@Flyzguy This is a bit anticlimactic, but apparently the question at 7:48 straight out demands a smooth shape. So I think the only reason he says the shape must be smooth is that the question said so.

[@saminu2965]

Thanks!

[@Kittycat-mr4im]

How does this have 0 likes

[@Emma-rw8yo]

I keep coming back to your videos because of your practical demonstrations. It helps me picture and understands that concepts you discuss in amazingly helpful ways, even if I've heard of the concept beforehand

[@beeble2003]

It's actually obvious that the two "mushrooms" can be any shape. Whenever light reflects off the mushrooms, you can just treat it as a new ray of light that's originating between the two foci. Whatever direction that ray is travelling in, it will always stay between the foci. Since it doesn't matter which way the ray travels, it doesn't matter what angle that part of the mirror is at -- in other words, it doesn't matter what the curvature is. It doesn't even need to be curved.

[@jari2018]

can it be a christmas tree (fractal)

[@batlrar]

Any convex shape, if I'm not mistaken. A flat or concave shape would presumably reflect light into the other half, although it would stay out of the opposite two 'pocket' rooms for the simple fact that any path it takes is the reflection of what it would have done in the original section with the opposite curvature.

[@beeble2003]

@@batlrar Reflecting light into the other half isn't a problem, as it's started between the foci, so it can't get into the pockets, as you say.

@@batlrar Concave is fine, too.

[@gildedpeahen876]

I was thinking a T shape w no curve would do it too

[@NSLikeableHuman]

So glad to see Nils’ channel featured here! I’ve been watching every single simulation on it the past year. They’re great!

[@anthonynelson6671]

This shape kind of seems like the perfect shape for a book shop, cafe, restaurant or the like in which people love to go because it has those nice and cozy shadowy bits wherein one feels all tucked away.

[@ivandasty277]

You and people like you never get old. This boundless curiosity and this boundless passion to ask and find answers is God's gift to anyone he loves.

[@niko2924]

i just want to say that its parents like you that give me hope for this next generation. i can tell these children have room to ask questions, learn, grow, and be themselves. its a beautiful thing, and a lovely contrast to the "i dont know" and "be quiet" responses i typically hear from parents when they are receiving questions from their children while they are out and about.

[@wilms2328]

That's always been an issue, if anything parents now are more attentive than they've ever been

[@Dalenthas]

Me, about a minute in: I wonder if Steve's ever seen Nils Berglund's simulation of this phenomena? Steve just after: Here's a simulation that Nils Berglund kindly gave me permission to use...

[@christophergeorgia9670]

It's amazing how he's able to make such simple explanations for such complex things. Keep up the good work 😀

[@mr.deathx4679]

I don't think i quite understand his simple explanation

[@christophergeorgia9670]

Oh no I just realized that when I edited the comment I lost the heart ☹️ it makes sense because if it didn't, somebody could just make a really nice comment, get a heart and then change it to something really mean.

[@SteveMould]

@@christophergeorgia9670 It's back!

[@christophergeorgia9670]

@@SteveMould thank you so much. That's awesome 😃

[@DanHarkless_Halloween_YTPs_etc]

@@christophergeorgia9670 Yeah, I've been through that too; quite disheartening. KZbin really ought to pop up a warning when you click Edit on a ❤'d comment that if you hit Save, you'll end up with a 💔.

[@nielskersic328]

Another great video from Steve, but also many thanks to Nils Berglund. Those animations are simply beautiful!

[@clockworkkirlia7475]

I've seen a bunch of videos about this before, particularly that amazing Numberphile billiards example, but I knew I was clicking on this just because your demonstration was going to be so cool. Awesome work!

[@Wahunganganshapunck]

This must have been the inspiration for so many of the apartments I've lived in.

[@wiktorszymczak4760]

I love how Steve makes science feel real and usefull. Like i "know" that all science is useful and real but it often doesnt feel like that.

[@tommyrobbins839]

Hey Steve, just wanted to say that I love how accessible you make otherwise niche or relatively abstract phenomena. Your videos are some of the best this platform has to offer but you bring a level of humility to your work that I think is invaluable. Keep being awesome!

[@hullinstruments]

That automatic sandwich machine is the coolest! I was lucky enough to inherit a fairly valuable antique version of the “sandwich making box.” It’s from my great great grandmother side from Italy, made by a small luthier’s workshop in the 1600s… to help supplement their income when they didn’t have enough violin orders. however the toilet paper tube used as handles…. rotted away sometime ago, and it was also missing the original Tupperware lid to spread the jam. I’m hoping one day to find someone that can replicate the original parts. I think it might be the only example of such an old automatic sandwich machine, and I’m just impressed the corrugated paper board has held up this long. A true family heirloom 😉

[@DenvaProbablyDraws]

Dude I never see KZbinrs shout out others who make the same content as them, that’s so respectable and even though i only see you sometimes I like you so much more now.

[@hellraiser7118]

I have a question, which i guess would be impossible to observe, but what if you have a mirrored cube on the inside, somehow say shined a laser in it, then sealed it, would the light eventually run out of energy? Or would it bounce around forever?

[@embarrassedbraincells]

.

[@AayanML]

The loss of energy from light is known as cosmological redshift. If the mirrors are 100% efficient and will reflect all light (including thermal energy) back to another mirror then the light will indeed bounce around forever, but mirrors will always absorb a tiny amount of energy and reduce the light's intensity over time as it's transferred into heat.

[@rp3351]

@@AayanML You'd also need an ideal perfect vacuum inside the cube.

[@ghostlypresence5362]

One way to crudely try this in an observable way could be using one-way mirrors, whether the laser could be shone into the cube from the external I don't know.

[@AayanML]

@@rp3351 Indeed you would.

[@NovemberRomeo107]

I honestly hope that your kids are able to keep this power of making things.

[@chaos519]

lol, funny other people just kill this creativity and its not a crime hope they can keep that alive too

[@Zeero3846]

It'd be interesting if there is a bridge that takes advantage of the acoustic properties of an ellipse. A highway runs beneath the bridge, but the elliptical ceiling just redirects all the sound back into the highway. Meanwhile, walkways running alongside the highway remain relatively quiet, and you can easily talk to passers-by on the opposite side despite noise coming from the highway.

[@jasonyesmarc309]

oh my god thank you for posting this. I have been having the hardest time finding radial light demonstrations of this room. It's been driving me absolutely crazy. EDIT: Will also be checking out Action Lab's video too! The problem I keep finding is so many hits on Google explain what the room is, but very few people demonstrate it in action with realistic or high-count light rays.

[@seankaelin8068]

You along with several other channels similar always seem to mirror each other but it's cool because you guys have you see me answered just different ways of conveying it which after watching all of you helps me better understand and learn how to convey to my kids

[@donotlookatmydesc7223]

Just the thought of that scraping around the floor gives me goosebumps

[@Brassblitz]

I wonder if this has application in bunker construction or designs interested in maximizing survivability? Explosive shockwaves are waves after all. Maybe simpler design considerations already maximize that protection though?

[@pterafirma]

The principle is kind of similar, the main difference being that giant (low freq) waves are more omnidirectional. Picture a massive pulse of air pressure, filling the volume - it wouldn't care about which way it's allowed to reflect. Look into acoustic design, and how a bass trap is made for music performance and recording. I'd bet it's a closer analogy to what you're aiming for.

[@jhsevs]

Or car audio

[@DanHarkless_Halloween_YTPs_etc]

MythBusters episode 191, "Trench Torpedo", had some beautifully visualized experiments along those lines. #162, "Running on Water", also looked at the topic.

[@AndrewGordonBellPerc]

I want to combine this with an anechoic chamber to create the weirdest sensory experience ever

[@MrNeosantana]

On LSD

[@lastdingo]

It deoes wok with rays, not with waves.

[@eric1393]

That original source is an amazing find, Steve! I wonder if any of the other puzzles are as fascinating?

[@aidanmatthewgalea7761]

things like this make it ever clearer why prof. Hawking loved Sir Penrose so much

[@OriAriel94]

I have a friend who lives at the top floor of a building where the middle of the stairwell, around the second floor out of four, is always so counter-intuitively dark even though the roof has a skylight and the first floor is illuminated. It's a really bizarre feeling going in and out of darkness without the division of a door or a curtain, instead just passing the point where light manages to angle around the corners and suddenly everything's lit!

[@noveprodco]

You've just earned my like since you've mentioned The Action Lab's video. That says a lot of you and must be rewarded. Not every content creator is able to do that with such an elegance!

[@doggonemess1]

That's so great that your kids are interested in engineering. I wish I had been encouraged more and discovered my love of it earlier in life!

[@timbonator1]

@Laura Brown is this like a joke or actual advertisment xD

[@TheVal1958]

It might

[@jhsevs]

Yes!

[@MattSeremet]

Please don't compare yourself to action lab, you're a great presenter and 100x easier to understand. That dude makes a lot of jumps in reasoning or expects his demos are perfect when really they fill me with more questions about their setup and less understanding on the whole. You talk about all your variables and it makes me actually feel like I know what's going on.

[@Ruslan-S]

They're definitely different but I enjoy action lab as well.

[@ZeKnife]

I don't want conflict between KZbinrs, but personally I don't see how anyone could learn anything from action lab, he just seems to point his finger at neat stuff without making any effort to explain it at all

[@MattSeremet]

@@ZeKnife such truth. It'd be fine if that was that: a cute demo, but it's only been like 2 minutes then another 1/3 of the video is an advertisement. Worse than cable tv. NGL I do watch some action lab because it's better than nothing and he doesn't lie, but I haven't given the sub yet.

[@HornadySetiawan]

I wish you're my father! What a fun life it'd be! 👍🏻💝🏆🙏🏻

[@dmoney2015]

The ellipse explanation blew my mind. That was very cool!

[@1a1u0g9t4s2u]

Really enjoyed your explanation of this subject. Yes, I viewed the other video yesterday but enjoyed your background information and research. Thinking about constructing mini golf ball hole similar to the billiard you showed. It will make the grandkids happy.

[@kmturley1]

It would be interesting to show real-life uses for this phenomena such as trapping sound waves for noise reduction or preventing sea waves hitting a harbour?

[@jasondashney]

Breakwaters already do that. Don't forget that nothing will be perfect, as Steve explained in the video how a point source light will work a bit different from a wave.

[@CharlieGosh]

It seems you're suggesting a method for folding a wave back toward its source, creating a new wave that's 180 degrees out of phase with the next wave, creating a dead spot. The pair of waves automatically cancel each other. The problem would be that the waves would have to have the same frequency/wavelength, but most of them would already be so.

[@viguiry]

It exists already with noise canceling headphones

@@viguiry They work very differently.

[@zachparker1787]

Such thing was used in ancient buildings especially earthquake areas like Japan and India

[@fallen3424]

I love the simulations Nils Berglund does! Great to see one of his featured on such a big channel!

[@StoveLad]

right! i was looking for this comment.

[@jsdp]

Me too! I saw his name pop up and I was very happy! And then it popped up another 5 times... very glad to see him getting some more exposure :)

[@Mickparrysstepdad]

Interesting for my loudspeaker design hobby, because light and sound are waves, and in a speaker, you want to avoid sound reflecting back through the cone. Stuffing helps but can cause other problems.

[@francescodeguidi]

Also violina are oddly a similari shape

[@CamillaLyn6]

9:00 das pretty neat, i support kiwico, i like the idea that kids are actually learning stuff that can help the community, young scientist, its neat :3

[@thelegalsystem]

I cannot recommend Nils' simulation videos enough, they are spectacular :)

[@wedot1]

Thanks for plugging Action Lab. I though I just saw a video on this, but didn't know where, or if it was you! I love the community awareness. Also great video.

[@kevinfox3875]

This brought me back to my school day when my science teacher let us have for reading, his copy of TNS, and my first year of science was 1958.. Loved reading it, even though I hadn't a clue what was being discussed .

[@elmagikarpmamadisimo9774]

Video: Penrose Unilluminable Room Me: * doesn't put a roof *

[@SpaceLaunchLabs]

Would've been cool if you bad different colored LEDs for the top and bottom halves so you could see the color separation

[@alpine9214]

Yes, please!!!!!

[@munchkinmeep]

I liked your unilluminable room setup very much, but the sandwich maker was absolutely inspired (and made me laugh audibly, because I was just watching "How It's Made" clips and it was yet another food machine!)

[@SteveMould]

Thanks! What my kids made is basically identical to what they have in those factories I believe

[@ThatRedHead717]

I'm begging you. Please make a suuuuuper long version of that one animation of rainbow light bouncing around the oval and missing the focal points. I want to watch that go for LITERALLY HOURS please I'm begging

[@fahrenheit2101]

Ask Nils Berglund - it's not Steve's animation.

[@AS-zm4jd]

obs

[@fakebadpeople]

It's truly cool to see it in action! The lack of a paper was a real plot twist.

[@rocketpower-8384]

I really liked the light diffraction animation at 6:00. That was a cool animation and uber relaxing to watch and try to guess!

[@sbsummit]

The first thing that occurred to me when I saw the room shape was, why does it have to be symmetrical around the horizontal? And sure enough, Penrose's original isn't. So you could do a similar example with just the top half of the room you created, and it would still be unilluminable. Also, shouldn't it be Penrose's Unilluminable Room, not Penrose Unilluminable Room? Don't be afraid of the apostrophe!

[@SteveMould]

Yeah, I had the same realisation. It's interesting that when you Google it, they're all symmetrical.

[@stevenjones8575]

@@SteveMould It's to throw the internet off the scent. You can make the bottom half any shape you want. So we know exactly what shape the internet would make it.

[@SpencerTwiddy]

@@stevenjones8575 peanut shape is infallible

[@JimC]

"Also, shouldn't it be Penrose's Unilluminable Room, not Penrose Unilluminable Room? Don't be afraid of the apostrophe!" It's not fear, it's just a convention. In the case of Penrose, it's for ease of enunciation because there would be 2 "z" sounds in a row. Then there's the Penrose staircase. For other reasons, Wheatstone bridge, Erlenmeyer flask, etc.

[@anon6514]

@@JimC The plural of rose is roses so there shouldn't be much a problem with this double-z sound But when you have two s like this, often the second is dropped and the apostrophe put at the end. i.e. Penrose' Unilluminable Room But I think the one in the video title is correct for the other reason you mention.

[@autumnrain249]

Make a pool table in the shape of a Penrose room, put pockets in each of the 4 rectangles, bet people money they can't hit balls into all 4 pockets from a single spot, profit

[@davidkain3555]

What about sound waves in a room shaped like this, an environment for audio engineers? Which shape would be the optimal near zero reflection room, at the listening spot?

[@DaftFader]

Anechoic chamber's are designed this way (for minimal reflections of sound), they have many differing sized spikes with different angled sides in dense foam to scatter any reflections. The best ones have like a cage inside and the floor is also done this way! You can hear your blood pumping round your body it's so quiet if no one is making a sound in there. People often find it hard to spend long periods of time inside with no other sounds, as we are not used to such silence and it messes with our senses.

[@danieldubinko9561]

Huge huge props for shouting out another account. Big respects!

[@christibritton1436]

When I was growing up in 1950's my parents would go to Eugene Toy & Hobby and buy me science kits - a chemistry kit, a radio kit, and I actually built a small steam engine. But 1960's education policies wouldn't allow a girl to take shop classes - very frustrating. We had a farm and with my dad, I built miles of fences, 2 barns and a small arena for our horses. So I did get 'on the job' experience, but not at the depth and variety wood & metal shops would have provided. Oh and we bought a surveyors transit at auction and surveyed our 200 acre property to be sure fences were inside property line. We traded off tasks, clearing brush, running 100 ft tape, setting next point, using transit & property markers & survey maps to set lines - no GPS in 1960's. Later in my 20's I wired my dad's new 4000 sq ft home- as well as other tasks, rough carpenty, roofing on a 3 story building . . . Eventually - in my late 50's I got my own wood shop, but wished I had been taught the finer skills of carpentry needed for furniture and artwork that I try to learn on my own now. [Profile pic is of a mouse sized wooden mouse that I designed & carved. ]

[@beaker_guy]

nice mouse 🐭 Wish I had a transit.

[@MH_Binky]

For the shape of the mushroom curves, an intuitive reason why they can be any shape so long as they don't go above the focal points, is that any ray of light originating from anywhere on those curves will pass between the two focal points from below them. Since the ray would be coming from below and between the focal points, either it hits the outer wall and is reflected back between the focal points by nature of it bouncing off an ellipse, or it hits the other mushroom curve.

[@madeintexas3d442]

Lol I had to say Im having deja Vu from action labs video lol. I definitely had questions after it though. I definitely appreciate the model used here it does show the concept a bit better.

[@battleframestudios8989]

That was wholesome to see your kids have the same love of making things that you do.

[@honorarymancunian7433]

That sandwich machine was AWESOME!

[@davidschmidt6013]

Good channel. Lucky kids. I'm a recently retired middle-school Science teacher, and I wish more schools would invest in those kits. Cheers!

[@ThatSockmonkey]

The first openGL code I ever wrote (at University, studying CompSci) was to generate a Penrose diagram with math. It made me fall in love with C programming language and the openGL API. This was back in the days when a NVIDIA TNT2 was a state of the art graphics card and my home computer took nearly an hour to render the output of the program. Then I got to compile and run it on an SGI system in the school research lab and it was instant haha. I almost ended up pursuing computer graphics as a discipline, but ended up going down the audio DSP route instead, and never really used my CS degree (I did a double, BSc CS and BA Audio Production) and wound up in Radio, but Roger Penrose has been a long time hero of mine. His ability to imagine and design weird, impractical and yet scientifically fascinating shapes and structures really impacted me as a 20something.

[@NoTimeLeft_]

5:27 Steve is a dream fan confirmed!

[@d.mort.]

I was watching this video until 6:20 just waiting for the answer to why the light didn’t defract around the corners. I was expecting a mathematical explanation but was left with “it does.” I was beginning to rethink my understanding of light 😭

[@Penguinmanereikel]

I’d buy you’re kids’ sandwich machine for a dollar! But for real, seeing your kids get excited for Kiwico was extremely adorable

[@kryppled]

everyone: places it down in the penrose room me, an intellectual: places it above it

[@algorithminc.8850]

Nice to see an actual physical demonstration. Great stuff. Thank you. Cheers

[@zariahnongrata2257]

Would this work with audio as well? Like, if you had a sound in a room this shape would there always be a silent spot?

[@Shimada.]

No I would say maybe not? because Sound works differently than light

[@zariahnongrata2257]

@@Shimada. I imagine you would have a similar effect to the the simulation depicting light as a wave form. I hypothesize you would have quiet spots but there would be a small amount of 'bleed'.

[@Shimada.]

@@zariahnongrata2257 that is true, my original Reply was longer and went a bit more in depth into this discussion but I don't have time for it right now sadly :( My opinion did turn around though when I remembered that sound as a wave would be similar to light as a wave but the difference is that sound needs a medium like air to travel through and light (for air at least) doesn't , though I'm working on this exact fact right now so I'll see.

[@MohamedHassan-oq4sg]

Actually due to wave diffraction it will be closer to the animation he did when he treated light as a wave, so you would hear the audio.

[@buycraft911miner2]

Sound would travel through the walls, as, unlike light, it can travel through solids

[@Chaud31423]

This'd be perfect for a top-down horror game

[@gregoryholder2423]

Ah the curse of science KZbin, to work on something only to discover someone beat you to it.

[@yuppymike]

Was just thinking the same thing!

[@Anklejbiter]

He got derek'ed!

[@joshquivey6990]

Well that's just frickin' WILD! Thank you, especially for the the physical model representations!

[@Isaac-LizardKing]

nils berglund is literally my hero

[@The_Galaxyshark]

It's interesting that the shape of the mushrooms doesn't matter, but is was wondering if the "stalks" of the mushrooms are necessary at all, or if they're purely there to allow construction from a single piece? If you instead had an elliptical room, with two pillars outside of, but in inline with the foci, would the effect still work? I assumed it would since all light would be coming from outside the foci and would, as you explained, never pass between the foci

[@someoneanyone7947]

well, if you look at the original problem posed, you can see that there it was different, there has to be any cavity there, doesn't matter what shape, but some cavity has to be there (else it wouldn't have to be illuminated)

[@killerbee.13]

The issue is that there are some places you can put the light that enter the space behind the mushrooms on one side, but are blocked on the other. If there were no stalks, the light would simply pass all the way under and come out the other side, illuminating the entire room.

[@mamatuja]

I was going to build my room this shape, but when I discovered I'm going to need 2 light bulbs to light it up I will not.😁

[@delphicdescant]

Also a lot of mirror surfaces. Because if you use regular matte wall surfaces it won't work at all.

[@mamatuja]

@@delphicdescant I'm sure I can get those at Home Depot with the correct elliptical surface curvatures. 😁

[@mr.pavone9719]

What if the you replace the little "mushroom" projections with round or even elliptical pillars?

[@cxvxcbcxn]

I want to get kids just so I can order KiwiCo crates for them and help them build it! Looks like so much fun, I wish I had that when I was a kid.

[@ioanstef1983]

Good Thing there is paint in every color and shade, to darken or lighten areas, as it is uniform walls that Penrose design needs! Interesting video!

[@nonsfearme5474]

my room is a great example of no matter where the light is, most of it will be dark

[@Netherexio]

Whoever invented this needs to make urinals.

[@R2Bl3nd]

I love this and I love Action Lab!

[@KipIngram]

Oh my god, man - I adore your kids! I have five of my own, and I remember the days of that general age range so fondly. How fantastic you've got them that excited over science - great job!

[@Caluma122]

Oh wow, KiwiCo, finally something a KZbinr has demonstrated that I actually would want 😂

[@ravensnflies8167]

after finding the backrooms, this room gives me palpitations. theres literally shadows around every corner no matter where the light is. gives me the creeps just thinking about it. never thought steve would give me the heeby jeebies:}

[@Toastmaster_5000]

I'm sure you could just get a still-frame of him being wide-eyed staring straight into the camera and make a giant print of it. I'm sure that too could give you the heeby jeebies lol

[@softwarelivre2389]

Two lights and the room is lit.

[@icebluscorpion]

This room can be a perfect disco room where every part of the room can be light in a different way if the focal points have different light sources🤔

[@ProudSkittles]

Could have been better to show how a normal room with straight top and bottom walls will reflect the whole room including the small rooms to see the comparison

[@FraktalPriest]

Thanks for the visual... I've used that exact round billiard table in a museum over 30 years ago!

[@Griffman1231]

9:06 THEY WHERE SO EXITED