Solving the mystery of the impossible cord.

STEVE MOULD FACE REVEAL! Check out Steve's 10^6 subscriber Q+A with me cosplaying as Steve. • FACE REVEAL - The 1M S...
UPDATE: We have a proof that if a cable goes back and forth under a handle an equal number of times it can always be removed! Thanks to Henry Segerman. (It does assume the cord itself is not knotted.) www.dropbox.com/s/h8r1wk7qo1w...
Huge thanks to Susan Okereke for helping out with the video. dothemathsthing.com/
Check out her podcast with Bobby Seagull: Maths Appeal
/ @mathsappeal2666
/ mathsappeal
This is the reddit post Steve mentioned. / dont_snip_use_sorcery
Whitehead link
mathworld.wolfram.com/Whitehe...
Cheers to my Patreon supporters. Without them I could not have afforded Steve's exorbitant KZbin consultancy rates. / standupmaths
CORRECTIONS
- I never make mistakes.
Filming by Steve Mould, Alex Genn-Bash and Matt Parker
Editing by by Alex Genn-Bash
Music by Howard Carter
Design by Simon Wright and Adam Robinson
MATT PARKER: Stand-up Mathematician
Website: standupmaths.com/
US book: www.penguinrandomhouse.com/bo...
UK book: mathsgear.co.uk/collections/b...

[@SteveMould]

OK, Susan Okereke's thing with the rope and the ring was really good. Shame though, I had this whole thing about tau planned.

[@victorscarpes]

@@TheFreeBrounfortunately i can't argue with you

[@notyourbusiness2672]

You are a bad influence on Matt.

[@SpeedLockedNZ]

Counter example... Did I just sub to the knot Steve Mould channel. (Nah, long timey subscriber oddly)

[@Games_and_Music]

I remember the rope trick as a part of a kids magician box set, those "40 Tricks in 1" sets.

[@chiepah2]

Great bit, true genius, was that you or Matt who thought of that.

[@hexeract9541]

Steve and Matt have better stage chemistry than 99% of TV romance couples

[@masu5000]

the rhombian dodecahedron video with Adam Savage was very stage chemical to. Not exactly TV romance couple like but...

[@miriamrosemary9110]

+

[@SpeedLockedNZ]

What would the children be like?

[@masu5000]

@@SpeedLockedNZ little smart aleck's I assume?

[@yumnuska]

If you ever get a chance to see them live, it’s amazingly fantastic.

[@WishfulOA]

“No you don’t need some props if you want 900 thousand subscribers” Absolute savage

[@100nodog]

That had me laughing for irresponsibly long time.

[@H34L5]

I found it in poor taste. The rat race to internet fame-dom, good people.

[@davidharris2517]

@@H34L5 it's obviously all in good faith

[@blindleader42]

@@davidharris2517 good *fun?

[@davidharris2517]

@@blindleader42 that would also work but "good faith" is a saying meaning they have good intentions and aren't actually being mean to each other.

[@gildedbear5355]

Look, I think the solution is to simply declare the number "900,000" as a Parker Million. Who's with me?

[@thelazy0ne]

Sounds legit. Imperial numbers, I lived my whole life thinking everyone knows that 1 ton is 1000 kilograms...

[@jimmygervaisnet]

XD

[@Coen80]

He got there! 1.03mill as i watched the vid. (9/aug/22)

[@TheHookUp]

This is only the 2nd knot theory video I've ever seen... the first was when Tom Scott tricked me into watching a knot theorist when he was on vacation. I enjoyed both equally, 1 million subs (or even 4 million like Tom) should be right around the corner.

[@domenkastelic2611]

Hey, I can't seem to find the Tom Scott video, anyone mind sharing a link?

[@neelotpaldutta2347]

@@domenkastelic2611 kzbin.info/www/bejne/Y5a5lWWLnNBseLc

[@andreizonga4611]

@@domenkastelic2611 I won't give a link here, because KZbin usually deletes comments with links, but the name of the video is "How knot to hang a painting".

[@kittycatcrunchie]

I was just trying to remember what the only other knot theory video I've seen was! Thanks :) Was also Tom's vacation video

[@Tyranitar66501]

There is another one about the London Underground by Matt as well.

[@lucbloom]

Steve lurking in the back is so hilarious 😂 Not gonna lie, they had me the second time as well.

[@-danR]

OK. But which one is Steve? And who's the guy with the beard and the eyes?

[@Esmio06]

The second one got me even more

[@rrni2343]

You don't need pilot holes when you can just make Parker holes.

[@NickNorton]

ba dun tishhhhh

[@danbrellis]

Underrated comment

[@theobserver314]

😅

[@HaloInverse]

I believe that falls under the broader discipline of "Parker Cabinetry", which includes such sub-fields as "Parker Handles" (almost but not quite in the middle of the door) and "Parker Screwing" (leaving screws loose so there's a bit of jiggle).

[@bluecat2991]

"I'm not used to working with physical props." Says the man who approximated Pi with a pie.

[@billr3053]

Or printing out Pi on 1.05 miles of paper almost 7 years ago. Talk about making something physical out of an irrational number.

[@trickytreyperfected1482]

Or who measured pi using many copies of his book and a large pendulum

[@ReedoTV]

Or who showed the double domino effect with bricks

[@efulmer8675]

Or who calculated pi using oleic acid and a bucket of water.

[@raphaelkox]

No mention to the giant protactor and pass-counter?

[@ethanandrews3076]

I don’t know why, but the idea of framing a picture of a book is hilarious to me 😂

[@DasGanon]

It's weird I thought he had the one off "Humble Tau" cover

[@nadijathajan20]

do not question the elevated one

[@miriamrosemary9110]

Definitely! The note from Matt though - talk about a friendly rub in the face 🤣

[@RFC-3514]

And then making a video of it.

[@vigilantcosmicpenguin8721]

Well, the whole book wouldn't fit in the frame!

[@Sam-ey1nn]

You really should title and caption this video "How to attach a handle to a cabinet door". You can always change it back after a few days, as Veritasium has recently expounded on.

[@MisterNohbdy]

Except that would be the bad clickbait Veritasium was not supporting, because it doesn't give you any useful information about the actual content of the video.

[@jsmith5443]

@@MisterNohbdy oh, but it does show you how

[@willguggn2]

@@jsmith5443 It rather shows how knot to.

[@benwisey]

“How to knot attach a handle to a cabinet door”

[@hughcaldwell1034]

@@benwisey I would totally watch How Not To Attach a Handle to a Cabinet Door.

[@7head7metal7]

As much it was clearly a joke, I still felt bad for Steve :D you guys are just so much fun together!

[@davidmoore1253]

14:45 I was expecting Matt to turn his camera around and show Steve in the same room the whole time

[@sorellana2154]

me too, lmfaoooo

[@ngiorgos]

14:53 I thought he would troll us and wellcome Steve as the "expert" 17:15 it happened again!! I'm dying from laughter! Poor Steve looks so sad though! 17:41 Matt please! You're killing me! XD

[@UserUnknown07]

That's just sad and funny. I bet it's Steve's Stand-up brain

[@wynchell.abanes]

Yeah. The final part's edit, plus the good positioning of furnitures really sold the joke really really well. Made me laugh. 🤣 Edit: Okay, I take it back. Looking at it closely, I'm not sure if it's an edit. Gonna finish the video. Edit 2: yeah! You're right! It happened again! WHAHAHAHAHA

[@kylanacus2407]

yeah its too bad Steve couldn't join them18:04. haha

[@reidflemingworldstoughestm1394]

Maybe if you gave us an update on the 3-sided "coin" progress you could reach that 1,000,000 subscriber mark.

[@captainsnake8515]

Pretty sure he said somewhere that it’s basically impossible because the probabilities are too dependent on the surface you’re rolling the die on.

[@reidflemingworldstoughestm1394]

@@captainsnake8515 Fack. Now I'm depressed.

[@Henrix1998]

@@captainsnake8515 why not assume absolutely rigid surface?

[@ahsdfkdasdahdkas2887]

@@Henrix1998 The only "perfect physics surface" is one where every collision is perfectly elastic, so no energy is lost. In that case the coin would never settle on the surface, it would keep bouncing. I think the only way to do it would be to code up a complete physics simulation and bounce every different coin off every different surface as many times as possible, which isn't really Matt's style.

[@DeNappa]

I fully expected the "expert" to be the all-knowing Future Matt

[@rivers4753]

Steve Mould - "You can't just do it on paper". Wait till he hears about Numberphile.

[@idontwantahandlethough]

They even have SPECIAL BROWN PAPER

[@Wouter10123]

Too bad they barely use it anymore. They've replaced everything with stupid animations :/

[@ragnkja]

@@Wouter10123 They haven’t replaced the brown paper with anything, they’ve just _supplemented_ it with animations.

[@Wouter10123]

@@ragnkja Yes, in such a way that you can't see the brown paper anymore.

[@Eldorado1239]

But they've added Ducks recently so my hopes are up.

[@AmmoBoks]

The race to 3.14 mil. subs I would imagine. :)

[@WesYarber]

I think Steve would prefer 6.28 mil.

[@AmmoBoks]

@@WesYarber Both would for the subs, but choosing τ over π feels like... sacrilege

[@dielaughing73]

3,141,592 I suppose (or ...93 if you round up)

[@jimjjewett]

e million is also worth a campaign Personally, I like the golden ration and 5^(1/2), but those *might* be too niche even for these channels.

[@GhostEmblem]

@@jimjjewett I dont think the golden ration is niche in fact I think its more mainstream than e. I grant you the root 5 though.

[@olgierdvoneverec4135]

Matt: literally bought the entire suply of torus balloons in the UK for a single video where he used one. Also Matt: I can't believe I have to buy a cord and a handle!

[@dielaughing73]

Has anyone got their torus balloon yet? I'm still waiting for mine in Australia.

[@hughcaldwell1034]

There is something unbelievably relatable about that. I'll spend hours on recreational maths or down random Wiki rabbit holes after listening to NSTAAF, but the moment someone asks me if I found my account number for something or worked on my assignment... "What the hell would I do that for?"

[@joshyoung1440]

@@hughcaldwell1034 what's NSTAAF? No such thing as... a failure? Damn, I'm usually pretty good at guessing acronyms...

[@hughcaldwell1034]

@@joshyoung1440 All but the last word correct, so pretty good! Especially considering it's No Such Thing As A Fish, which I'm not sure anyone not in-the-know could guess.

[@JohnHoggard_aka_DaddyHoggy]

Oh, my heart, the pathos when Steve comes into the room and then sneaks quietly out again... Well done, you guys.

[@TDLightt]

Steve awkwardly closing the door had me laughing so much I had to rewind for Susan's intro

[@henryrubenfischer]

This was absolutely hilarious. Also please do invite people over more often, it really livens everything up a bit

[@pyglik2296]

That ending truly is the biggest crossover in youtube maths history :)

[@hughcaldwell1034]

Damn it! Was that pun deliberate? Because this is a criminally underliked comment.

[@korumann]

I tend to find knot theory topics rather interesting because it's so cool to see how much thought and research has been put into the topic. Also I love that knot theory videos tend to fall into one of two categories; 1. "Knot theory exists and is a real field of mathematics" 2. "How to perform black magic using knot theory "

[@chrishill601]

Hough Hunt is actually who I was thinking of before he showed up. I always loved the videos where you went to see him!

[@UnderfundedScientist]

The bit at the end was absolutely hilarious

[@matthewkaseman7457]

The plug? I mean, I know that British electric standards are funny and weird, but I don't know if I'd call them hilarious.

[@zanedobler]

Alright everyone, unsub from Steve’s channel until Matt reaches 1mil.

[@joeylehman9649]

😂

[@sadhlife]

@@maker0824 at least you can say you unsubbed

[@CarstenSvendsen]

I was super confused as to why Steve Mould was on the screen in the beginning. I check my subscription status and I'm subscribed, which is I'm not to Steve's channel because I don't like him. Then I check the channel name and it's stand up maths! Aah he's a guest.

[@ignacioelia759]

Ha! Matt liked this idea a lot, it seems.

[@Crypt4l]

I will if Matt does^^

[@Verlisify]

I do like the commentary on how social media has raised expectations beyond straightforward explanation.

[@joseville]

Hey @Matt Parker, you already have 1,000,000+ subscribers... in base-9, which is a perfect square! (love your videos)

[@deefdragon]

Steve looks SOOO sad at 15:05 and, while I shouldnt find it funny, I really do.

[@LeoStaley]

Well they put it in as a joke, so of course you should find it funny.

[@UserUnknown07]

And at the end too !

[@aikumaDK]

Given the scar on his forearm, I'm not surprised of Matt's aversion to practical/applied maths.

[@captainobvious.29yearsago70]

he got it in a terrible division accident, you see

[@rewrose2838]

he got it from his new pet, I asked the same on a not so old video

[@Crypt4l]

I really want to know which crazy video idea go him that.

[@vigilantcosmicpenguin8721]

Math, a very dangerous field.

[@willguggn2]

@@vigilantcosmicpenguin8721 Math - not even once

[@brandthagen4490]

Alright I’m a knot theorist now. I didn’t know that was an option

[@notmyname327]

I'm not

[@fares8005]

I'm the conjugate of a knot theorist. Not a theorist.

[@CeeJMantis]

It's a knot option

[@brandthagen4490]

@@CeeJMantis knot funny

[@brandthagen4490]

@@fares8005 now you’ve got me all tangled up and confused

[@17-.]

Been watching your videos for years matt. So excited for you

[@theodoreroberts8524]

That knot is used in climbing for belaying, it's called an Italian hitch (in the UK at least). The handle would be a carabineer and then you can adjust the crossing rope to either let it slide freely to allow the person you're belaying to climb, or clamp the crossing ropes together to catch them if they fall. Flipping that knot through the carabineer like Matt did through the handle, reverses the direction so it can then be used for abseiling.

[@idontwantahandlethough]

You should explain what abseiling is for everyone else. I totally know what it means. But other people would probably appreciate it. Again, not me though, cause I definitely already know that word....

[@hughcaldwell1034]

@@idontwantahandlethough Rock climbing but downwards, essentially. Actual climbers/abseilers will probably chew me out for this. The word I'm unfamiliar with is "belaying", but this is an interesting comment and now I'll go look it up.

[@SimonBuchanNz]

Falling with style? I mean, not much style, but more than regular falling.

[@hughcaldwell1034]

@@SimonBuchanNz Falling for people who don't just rely on being caught by a giant bird half way down. That would be utterly ludicrous...

[@idontwantahandlethough]

@@SimonBuchanNz *YOU. ARE. A. TOOYYYYYYYY!!!!!!!*

[@expchrist]

3 minutes in and this is already the BEST standup maths video I've seen in a long time :) Pun at the end was great.

[@TheFacelessDrummer9]

I was wondering when we would see Steve show up to gloat over his victory! Love the collab videos

[@ericvaninwegen6384]

Susan's "Thanks for roping me in" comment rings pretty true!

[@danielmann6772]

I see what you did there... "rings" pretty true 🤣🤣🤣

[@oz_jones]

Please, could you knot do that

[@ngiorgos]

Yes! Finally!! I've been waiting for this since Steve chalenged you!!

[@skykincaid5644]

Steve: Hello it's Steve Mould here. Don't panic Matt will be here in a second! Me: Why would I panic? I think you and Matt should collaborate more often!

[@JD-lx2yf]

Do not stop these types of videos. Its great seeing the two of you work with each other.

[@Hassaan911]

The video was absolutely amazing and entertaining to watch till the last minute. Loved your spirit and Steve's expressions! 👍

[@jenschristiantvilum]

15:13 That gag is worth 1M subscribers!

[@TheMightyBigga]

I am genuinely surprised this channel hasn't exceeded a million subscribers a long time ago. I would have guessed 5m easily.

[@idontwantahandlethough]

lol I think you might have forgotten how absolutely *_terrified_* the general public is of math... we are not normal people in that regard. That said, people like Matt are so incredibly necessary precisely _because_ people are so scared of math. He makes it approachable and fun and super interesting, even if you aren't a math wiz. I think that's a hard thing to do with any subject, but math especially. Both these dudes are just fantastic teachers... and that's like the coolest thing to be good at in my opinion.

[@tangyspy]

+1

[@Squant]

@@idontwantahandlethough I think you mean bored. I enjoy Matt's stuff and also Numberphile, but without those people making it fun... nah.

[@bretunderhill4178]

This is so good. The humor hits home. Please, more content with you and steve.

[@heathgoodrich670]

You guys are hilarious together. I can't wait to see what you two collaborate on in the future!!

[@x--.]

I have not laughed so hard at a KZbin video in a long while. I have been Steve at 14:55 a few too many times. Brilliant work.

[@pvic6959]

15:00 i laughed wayyyyy too hard at this!! AND 17:22 LOLOLOL

[@evanknowles4780]

I’m loving these topology videos, Matt!

[@gutobernardo7457]

The knot challenge at the end really looks like magic tricks I've seen around. Not sure if they use the same principles, but also cool!

[@Crucidal]

Hi Matt, I usually feel no incentive to subscribe to any channel because I feel like "the algorithm" already considers me a subscriber of your channel. All of your video's, as well as Steve's pop up in my feed already. I enjoyed the face reveal and the jokes in this video so much that I'd like to contribute 1 millionth to your goal. You're both making great video's and I hope they'll pop up in my feed for years to come. regards, Chris

[@GC-ps9mn]

Thanks for explaining this! I didn't even know knot theory was a thing.

[@madi112233]

This is the best math collaboration I've seen. I really appreciate it!

[@haydencotton3568]

Absolutely love this collab. You two are both hilarious and I always enjoy the banter. I can feel 5M subs around the corner for you both!

[@lhpl]

Hm, the font on my phone is too tiny for my eyes. I read that "5" as an "S"...

[@SaschaAlexD]

As some others pointed out already: At 16:01 Susan ties a square knot whereas at 16:36 Matt shows the diagram of a granny knot The puzzle becomes way harder like this!

[@HansLemurson]

Glad to see Matt getting a handle on things.

[@emiltoteb]

This is so far the best door handle installation video I’ve seen on KZbin.

[@wynoglia]

This banter has been the highlight of my year

[@troseberry91585]

@4:44, I think we should start a museum for this type of art. Call it the MoMA or something that's never been named that before. The Museum of Meme Art.

[@pangiokuhli512]

the MeMa, if you will

[@blindleader42]

I don't _think_ it matters to the puzzle; I'm not a topology expert. But: 16:01 Susan ties a proper square knot (reef knot) 16:36 Matt diagrams a _granny_ knot... For Shame! 😡

[@BillRicker]

Oh but it does matter. You are right to note that Past Matt got the diagram wrong here. It likely would also be possible to retrace a granny knot into an unknot, but i suspect it would be quit different sequence from the moves Susan showed, which do undo a square or Reef knot. (The symmetry of the reef knot may be aiding us??) HINT it's easier to practice unknotting the reef without the ring 💍 first. Then add retracing the ring transit after the other moves are good.

[@daddymuggle]

Three months later, I came to say the same. Scrolling, scrolling, scrolling... I was starting to worry that no one else had noticed.

[@danieldaugherty918]

oh thank you for pointing this out I didn't think to check whether this was, in fact, Susan's knot. and I was having trouble mapping it in my brain. a square knot will be easier.

[@tyllatyllatylla]

@@daddymuggle Yepp, me too! :)

[@giovannipezzin5707]

The best kind of competition, collaboration. Great video!

[@Noxelius]

finally! I was waiting eagerly for this. Thanks!

[@tparadox88]

Matt: commissions epic music scores for videos, high quality animations, bakes lemniscate biscuits... Also Matt: "you want me to go out and BUY a handle and extension cord?"

[@SVoided]

Reminds me a bit of festival of the spoken nerd when they were pressuring Matt into using props to show a torus

[@twojuiceman]

That's a triple integral for crying out loud! That alone speaks volumes!

[@SVoided]

I didn’t realise we had a mixed ability audience in tonight

[@hughcaldwell1034]

Yeah, me too. Unfortunately there was no good reason to re-hash that triple integral joke, because that is still one of my favourite things to come out of anyone's mouth ever.

[@RealHypeFox]

Trying to help Matt’s new maker channel with the algorithm. Pilot hole, drill, handle, door, cabinet, cabinetry, DIY, how to, troubleshoot, interior design, future proof, handle.

[@Skyben2]

I'm loving it watching you two having fun!

[@maxmustermann5932]

Using slot screws (4:39) to bolt down the handle, ouch. Philips screws (+) or even better: Torx screws (wavy hex shape) are much easier to handle.

[@MegaRad666]

Wow, great work Susan! I guess Steve did ok too.

[@LukeLane1984]

I used to do that last demonstration as a magic trick back when I was a magician years ago. I had several variations of it, too. It can be found in almost any beginner's magic book. But it's still cool to see and with the right presentation it can really stump people.

[@ClintWebb]

I've watched many of your videos before, but didn't realise I hadn't subscribed. You've got yourself one more subscriber!

[@piast99]

I can guarantee that there will be some impossible knots on the door handles when I'll go to the work next monday.

[@BlackIceDry]

"I'm not used to working with physical props" says the man who printed 261 3d net models of 4d cubes...

[@zka77]

15:55 now we know who to call when the iphone's headset needs to be untangled ps: this was the funniest and most wholesome video I've seen recently, big thanks and grats

[@missyc13]

lmao the bit where steve comes in all excited and Matt introduces Susan cracked me up!

[@Czxvkq]

"no pilot holes, just go straight in" come on Matt, that's no way to please a cupboard door

[@mynameisneo7]

"But, I'm knot a theorist." -- 6:44

[@Belgarath1966]

Alright the bit with Steve Mould in the background is completely awesome. Loved it!

[@yland6003]

Subscribed because of this video! Good luck on your road to 1 million!

[@Jordan-zk2wd]

17:56 is that one professor's friend from Nunberphile who could have a good sense if a number was divisible by other numbers intuitively? I forget his name but it looks an awful lot like him to me rn. Edit: Norrie I think was his name, it's divisibility by 7 he can sense IIRC, and it does look like him : )

[@joonasjurgenkisel5480]

13:31 I imagine a proof for "whenever we loop something around a handle with same amount of pass-unders in either direction, it can be untangled" would go as follows: Traverse the cord and take the sequence of 1s and -1s you get; suppose we have N of each. In the case N=1 it's easy: the sequence 1, -1 (or -1, 1) corresponds to something passing in one direction and then looping back and passing under again in the same direction. This constitutes a "free loop" which we can just move across to the other side of the handle, cancelling both (in the physical interpretation, may need to move the plug through the loop before but this makes essentially no difference). In the case of larger N, our sequence must have some point at which a 1 and a -1 are adjacent. This corresponds to a free loop, which we deal with as in the base case and reduce ourselves to the case N-1. By mathematical induction, we are done. EDIT: As regards the actual challenge later on, we can view the rope as a cord and the ring as the combination of a handle and the door it's fixed to. When we first put the ring onto the rope, that corresponds to an underpass in one direction. The double knots that follow are done in opposite directions and therefore wind up cancelling each other out. Finally the end of the rope is passed through the ring again, corresponding to an underpass in the opposite direction. So in fact the whole problem is equivalent to the initial "impossible cord" one, just with more curves in the cord itself.

[@tempestaspraefert]

This would also prove that you can untangle the whitehead link, which is impossible. The problem is that a "free" loop can have a piece of cord passing through it, in which case pulling the free loop under the handle makes the piece of cord into a new loop.

[@joonasjurgenkisel5480]

@@tempestaspraefert Is this referring to the first or second part? Because in the first part the ends of the cord aren't attached to one another which makes this not a proper Whitehead link.

[@ohkay8939]

Always enjoy your videos :) No idea if it has any appreciable impact on viewership numbers, but one difference between yours and Steve's videos, is Steve always has captions on his videos. I'm not deaf or hard of hearing, and while English is my second language I do consider myself fluent and you always enunciate clearly. But I always have closed captions turned on when it's available because it gives me those words in your explanations that I'm not familiar with. Just one random person's impressions, do with it as you will :) (as long as you keep making videos).

[@TheyCallMeNewb]

A stellar example of our oh-so-certain (and convincing) intuition failing us spectacularly. These two have a terrific comradery.

[@ambbarnes9839]

I came here to find out how to put a handle on a door

[@Jacob-qx4bc]

woo i love maths

[@100nodog]

I do too, Dog from Undertale

[@Whaddif_]

Matt: Here’s your handle Steve: *and here’s your spout* 😀

[@kelvin0mql]

OK… the Steve Mould final 2 cameos have put me over the top. Now subscribed.

[@ethangertler]

How much for the Stand-Up Maths official "cabinet door" art piece? I need one for my office.

[@1BlessEdYou]

As complex as some of this is, the thing I was most astounded by was how Steve's earpiece managed to stay in under tension for his whole segment...

[@dragade101]

knot puzzles just got a lot more interesting. Thank you.

[@DavidBeckwitt]

This was comedy and math gold!!! Thanks you two!

[@Celthiccness]

Steve? You're not Matt.

[@leirumf5476]

13:47 Can't you prove it by induction? (I have little faith the next proof is fine) If there's 1 → and 1 ← then it's the trivial case that was already studied here. Let's assume it's true for n → and n ←, then in the case of n+1 → and n+1 ← we know that we can reduce the "knot" by n due to it being true for n and we arrive to the 1← and 1→ case which was already proven. QED

[@ngiorgos]

That seems like a good approach but I think it needs expanding I'm not sure we've seen all the +1-1 configurations. Maybe there could be an unsolvable one? Though I can't imagine any exame... Also, maybe for some (n+1) there is some configuration that does not reduce the pairs under the handle??

[@leirumf5476]

@@ngiorgos Yeah, all your remarks are valid. I wouldn't dare say what I scratched is in any sense rigorous or okay, but I do believe if such thing is true, induction might be the way to go

[@ngiorgos]

On a completely different approach, I think any knot can be untied if theres one free end, right? Our case is a knot with a free end, that's linked to a ring, but the free end cannot pass through the ring So, if we keep passing the strings back and forth through the ring, maybe we can eventually untie it??

[@leirumf5476]

@@ngiorgos Mhm, I think the trivial case with 1 ← already does not work, right? I'd even make the bold claim that: It's possible to untie it ←s = →s (Call it the Parker conjecture, that way if I'm wrong I won't be that ashamed for it)

[@ngiorgos]

@@leirumf5476 (facepalms) you're right. It must need the positive crossings being equal to the negative crossings. After all, this what Matt hypothesized as well.

[@TepidTake]

Absolutely amazing video. You'll get to 1,000,000 subs here soon

[@youtubeusername1489]

Steve's reactions are spot on

[@PapaFlammy69]

What a coincidence lol I just recently posted about this on my channel, including a puzzle for STEMerch EU^^

[@ianmccall1789]

Hello math daddy

[@csours]

Steve Mould? The one with one million subs?

[@xdcountry]

The Susan intro bit was great!! Amazing stuff!!!!

[@jpdominator]

Hahaha. The end. So awesome. Steve, you’re wonderful.

[@benjaminknudson5997]

I simply love how steve, after seeing that matt had an earbud in is ear, put the cap to a marker in his ear haha that sharpie cap is in there pretty deep steve..

[@NorbiCircusArtist]

There's a series of diabolo tricks called "magic knots", which include basically following the maths rules mentioned in this video (everytime to tie up the diabolo from one side, you have to do an equal opposite tie). So when I first saw the plug video, the solution was quite intuitive. There is however one trick which I've been doing for years, and it still blows my own mind every time I do it...

[@robandsharonseddon-smith5216]

The only mathematician on KZbin who actually makes things make sense... now can you sort out my headphone cables?

[@emrikplaysgames2604]

By the way, I LOVE the Steve + Matt dynamic duo. Do more of them! On both channels!