Domino Addition - Numberphile

Matt's Big Domino Computer: • The 10,000 Domino Comp...
More links & stuff in full description below ↓↓↓
More of this interview: • Dominoes Computer (ext...
Computerphile: / computerphile
This video features Matt Parker: / standupmaths
Numberphile videos featuring Matt: bit.ly/standupm...
Support us on Patreon: / numberphile
NUMBERPHILE
Website: www.numberphile...
Numberphile on Facebook: / numberphile
Numberphile tweets: / numberphile
Subscribe: bit.ly/Numberph...
Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): bit.ly/MSRINumb...
Videos by Brady Haran
Brady's videos subreddit: / bradyharan
Brady's latest videos across all channels: www.bradyharanb...
Sign up for (occasional) emails: eepurl.com/YdjL9
Numberphile T-Shirts: teespring.com/...
Other merchandise: store.dftba.co...

[@kfftfuftur]

His famous words: I may have done this

[@camwyn256]

I love it. Brilliant demonstration of logic gates.

[@numberphile]

camwyn256 thanks

[@dosluke]

Numberphile this is my favorite person, of all the professors that Numberphile uses. :)

[@dosluke]

Dosluke idk like seriously, I love this guy and every vid with him in it XD

[@0EEVV0]

wow thats kinda cool, i know how a computer works inside out, time to build one with 20 dominos xD

[@KoHaGames_]

Idk... I dont really like it, because it's useless after just one use. He could have chosen a Lego train or something for that.

[@sth128]

So what you're saying is that... THERE ARE BILLIONS OF DOMINOES IN MY COMPUTER!? Now I know why it's always making that clicking sound. It's the dominoes falling over trying to add 1s together!

[@samd3275]

Yeah, pretty much. It's just energy being input and output through different channels. Watch out, there's dominoes in your DNA, too. And in the air! And in your food! And in pretty much every element and chemical and substance and light particle and, well, the entire universe actually.

[@TheNBKiller]

Except, with dominoes, the ouput can't be turned back off. Once you've used your line of dominoes you have to set it back up, manually.

[@keiyakins]

I mean, when you get *way* down in the physics, it is a series of electrons pushing each other around... So kinda, yeah

[@jlp1528]

I always thought it was a hamster...

[@30IYouTube]

, storing your data, AND multipling via latchs, registers, flip-flops, and addition, as well as a flip switch so that addition becomes subtraction, and multiplcation becomes division, and the multiplication is controlled by, you guessed it, the repeat bit.

[@Dombowerphoto]

Give me 2 numbers between 20 and 50. Brady 42 and 17..... Bad maths there Brady.

[@noahwelikson1100]

Dombowerphoto I

[@Dani0x1B]

A teacher once told me "give me a 2-digit number" ad I immediatley said "one hundred and-". Thinking under pressure is hard.

[@MrScotteh]

one hundred and negative one

[@knightvertrag]

Should have been 27 🙃

[@rhandhom1]

They're Parker numbers.

[@Irishcrossing]

For the longest time, I was wondering how in the world computers actually worked other than "This is Harddrive, it saves and boots stuff." Ironic that dominoes helped me understand than any form of computer expert.

[@abexuro]

I feel the sudden urge to build a 4-bit addition calculator in Minecraft...

[@thetntsheep4075]

abexuro What about a 16 bit computer? I love mine :)

[@veristianarvico1281]

haha

[@georgesmith3292]

where is it

[@Megaman-ws8ik]

I had the same urge, so I did!

[@softlysnowing3959]

I did that, after reading his book

[@robbiedart7422]

At first I was unimpressed but I soon came to believe that this is possibly the best numberphile video so far! This is an ingenious way of explaining computer gates, made me excited!

[@adheesh2secondsago630]

If this was best, you are yet to meet Klein bottle guy.

[@mohammadahmedragab837]

I agree with you

[@gfetco]

That's it! This is the way I am gonna introduce Boolean algebra to my future students. I love how you can introduce applications in maths that even renders it interesting to the common man, it's an absolutely ingenious method that can spark enthusiasm to those who originally had none. Beautiful.

[@janosfolhoffer5239]

+Enlightenment this video made me to start computer science and learn a programming language on my own (even though i am just 14 ) :) Indeed this is beautiful :D

[@thetntsheep4075]

PainDespairForlornEnlightenment Use Minecraft! same thing but so much more convenient.

[@_modiX]

Now build a NOT gate with dominos.

[@janosfolhoffer5239]

+modi X Dude these are just dominos :)

[@_modiX]

+Janos Folhoffer simulate one, like in the video. :D

[@_modiX]

***** Actually I'm a software engineer and know about those things. In practice they work by using resistors, diodes and transistors. I was just trolling ;). The problem on the NOT in this kind of simulation would be, it cannot simply output 1 when no domino is triggered. You could solve it with a power connection that will not be cut up when the input is false, so the output gets true. In this simulation this would be cheated, though, because other examples are not powered separately.

[@Qbe_Root]

+modi X Two dominos: the input is a balanced heavy domino, and the output is a lighter domino which is already fallen. If the dominos are placed very accurately, the input falls right on the end of the output and balances it. #TrollPhysics

[@janosfolhoffer5239]

Qbe Root you're going to be my favourite guy from now on ... :D

[@schnapps77]

13:40 "Want to give me 2 numbers between 20 and 50?" "Okay, 42 and 17". Since when is 17 between 20 and 50?

[@gnetkuji]

I want so badly to +1 your comment, but I don't want to spoil the 42 it already has.

[@ja-vishaara]

since..... screw natural order of numbers!

[@piguy314159]

schnapps77 And afterwards, when Matt himself chose interesting binary numbers, one of them was 55.

[@Catishcat]

1=30

[@htmlguy88]

+schnapps77 maybe under p-adic numbers ?

[@frillneckedlizard8529]

this brings back memories of me making a computer inside of Minecraft, that was the first time I actually understood computers

[@xmame100]

Same, it taught me about half adders and full adders and how binary operators work

[@ckmishn3664]

I wish he would have shown a "not" gate where knocking nothing over caused a domino to be knocked over.

[@andreyutiamco9201]

Patrick Wise lel

[@zeikjt]

Easy, just have a single knocked over domino.

[@ckmishn3664]

That's what a "1" going through a "not gate" would look like, but not a "0"

[@zeikjt]

Ah you're right. Maybe a knocked over domino on the floor, and a single standing domino on top of a table? If you do it just right then maybe the one falling off the table has a chance of hitting the one on the floor in such a way that it'll spring back upright? Haha, that's the best I got.

[@ckmishn3664]

I only brought it up in the first place because I didn't think it was possible to do with dominoes. The thing is in electronics a "0" still has some tiny amount of current that a "not" gate can recognize as when it should turn on a "1". At least that's how I believe it works.

[@GigaGalacticGamer]

13:55 - "So we're gonna add 42 to 17. A bit of a *spoiler alert*, we're expecting 59" XD

[@MiriamLylac]

I always wanted to know this, and when I asked people "How do computers/calculators work?", I really meant it. I know I still don't have the big picture, but thank you so much for making such a clear demonstration on the subject!

[@UltraWindow]

binary>decimals you only have 10 fingers, but if you count on your fingers in binary then you have 1023 values. 4 to you all

[@lucromel]

I gave you're comment a 1.

[@ulicqueldromal]

I actually trained this in school and then started to communicate with a friend in ASCII using binary finger numbers. I probably don't have to tell you this, didn't go long, it's very slow...

[@zachrodan7543]

nice

[@repeaterlanes8024]

I'm surprised no one pointed out the fact 4 in binary on your fingers is the middle finger-

[@nemesisurvivorleon]

this entire exchange must be saved for posterity

[@cemalettincembelentepe8943]

Years ago, when I was at the end of high school, I watched this video and for some reason I loved the topic. Now, 5 years later I am going to start my Master's on computer architecture at one of the best universities of the world on this topic. Came here to write a you a thank you Matt!

[@TubeDude78]

This is absolutely phenomenal. Than you so much for it! It takes me back to my Computer Engineering class in undergrad when we actually built a working binary full adder from transistor circuits. Matt, I totally get your "disproportionate excitement" at the thrill of seeing the underlying mechanics of our digital world in action! I look at that class project as one of the highlights of my college experience. This is truly a masterpiece!

[@voveve]

"disproportionally excited" is what I feel of this videos!

[@Starter61]

With videos like this, I just love Numberphile more and more. Boolean Algebra done ....using Dominoes ? What an insane idea ! My deepest respect, Sir !

[@FernieCanto]

I am astonished. That is an incredibly clever and creative way of showing how computing works in a physical and fun way. It should have been stressed that the dominos that "block" a signal are a transistor, which are the heart and soul of any digital circuit, where the real magic happens. Once you can picture that in your head, digital circuits become immensely fun and exciting to learn.

[@Kanglar]

Dominos addition: 1 pizza + 1 pizza = 2 pizzas!

[@awesomedude7576]

Kanglar lol

[@adizmal]

Toto Troll, wrong. 10 pizzas = 1 *free* pizza. Everyone knows about the Domino's Rewards Program.

[@pedrodemello3666]

More like "Domino Addiction".

[@JLukeHypernova]

+Petrov Theovsk i thought that was what it said when i first looked at the title

[@lourier3]

Make a not gate with dominoes. :P Before knocking it over it'd need to be knocked over already and when you knock it over it would somehow need to put itself straight up again. If anyone can find a way to still make one, I'd be really interested! ---But don't just invert the 0 and 1.

[@JoelSjogren0]

Make a xor gate and set one of the inputs to true.

[@Hwyadylaw]

Simple. You do it the same way you do an electronic NOT gate. You use two lines. Line 1: Just a plain line that is always tripped; this is the output. Line 2: This line breaks Line 1 when it falls; this is the input When line 2 is NOT flipped, line 1 falls all the way through. When line 2 IS flipped, line 1 will be broken and NOT fall all the way through

[@thatoneguy9582]

MC_Mac_MC Knock a straight line over a record it in reverse

"Disproportionally excited"

[@OGjimbo]

Somebody needs to show this guy Minecraft.

[@1987Videolover]

he can literally make any redstone puzzle look very easy even the hardest one..

[@honggiakhanh]

that was 150weeks ago haha xD

[@abdullahenaya]

Yeah

[@fdnt7_]

hahaha xDDD

[@thetntsheep4075]

Minecraft is pretty much the same :)

[@ns88ster]

Over my many decades of interacting with computers casually, I have always craved this knowledge. My sincerest thanks for explaining it in a way I can finally understand.

[@DeviousMalcontent2]

10:20 I once hacked the pentagon from Microsoft paint.

[@WingmanSR]

I really appreciate the spoiler alert, I prefer the suspense.

[@tggt00]

redstone! anyone?...

[@2013danrazor2015danrazor]

nein

[@theoriginaltubeofyous]

There are much easier ways to make AND gates with redstone...

[@ItsSoooooFluffy]

Yes! I made a calculator in Minecraft made of adders which do the same thing. It's on my channel (warning: it's quite an old and crappy video)

[@アヤミ]

Red stone is powerful, goes over 15 meters and it still did not off

[@sriramaniyer9415]

Here

[@IMortage]

In none of the previous videos was his smile so genuinly happy. In a giddy kid kind of way. A pleasure to watch.

[@ceruchi2084]

I love how impressive "four-digit binary number" sounds at this scale... and then you remember that the biggest one is 1111, or 15.

[@EvilKimau]

*Amazingly Awesome Domino Math* This is where teaching should start at the low level not the high level. You can then skip up to a useful level but the basic understanding is key. The amount of kids who learned this from Minecraft Redstone circuits is just brilliant as well.

[@nickm2137]

I love seeing stuff like this being explained with physical objects.

[@SharayaYT]

I will actually give an exam at university on logic circuits, combinatorial logic, sequential logic and stuff like these and i am getting super exciting over dominoes, Matt is a great teacher.

[@westerp]

Having made full adders with NAND gates at school this wasn't new for me, but I enjoyed the fact this was done with DOMINOS :) You should do follow up with NOT and show you can do everything with AND + NOT using Karnaugh maps and boolean algebra.

[@comochinganconesto]

Best explanation of the adder ever. I love how visual it is.

[@ihategoogle2382]

I wish Matt would write a book about Domino computing

[@evanharriman9979]

So glad to see Matt Parker back! This is what gets me truly excited about computers! Thank you guys for putting in the time and brain power to carry this out

[@ImrazorZodd]

Oh how much more fun my electronics course would have been if this was their approach.

5:33 There's the magic sentence: "I'll give it a go." Totally different context now, but I can't stop noticing it when rewatching older videos.

[@Stonerman023]

Matt is just great, such enthusiasm. Such logic:D

[@caballeroPL]

This is great. it's what I learned when I studied electronics. But we only draw logic gates and explained how semiconductors create those barriers for blocking signals. Seeing it in action is brilliant.

[@jan_wh1tey]

I do all my calculations via dominos

[@emeryshurpit8656]

Just bring a couple Dominos to calculus! You'll be fine...

[@Gold161803]

SciencecraftYT // Sci You might need some infinitely small dominoes if you want to do calculus. They're pretty pricey, I hear.

[@emeryshurpit8656]

Gold161803 Just a tad bit

[@Sora_Halomon]

I doubt you're reading comments on multi-year old Numberphile videos, Brady, but this is probably my new favorite Numberphile video. I've always wondered about the very very fundamentals about how this kind of logic stuff works, and binary, and reading about it elsewhere has just made my peabrain struggle, so I'm glad to have found this all of a sudden.

[@slendy9600]

Does anyone else know what hes talkin bout cause of minecraft and redstone?

[@dutchpropaganda558]

slendy9600 totally

[@JorgetePanete]

slendy9600 he's*

[@noclipangel]

I loved watching this video. It clearly explained how basic logic gates work, in an enjoyable way .

[@Hevesh5]

Interesting video! As a domino builder myself, I could predict the results before you explained them :D

[@bpdolesdominoes4]

Me too :)

[@AV-op4oz]

yay

[@OonHan]

hi i am a fan

[@xTerminatorAndy]

I'm so glad you're on here too @hevesh5 I was just thinking of you when I saw this video

[@nilen]

That is so cool!

[@energysage9774]

Great timing on this video. One of my Physics professors decided this week that we should all understand digital logic circuits by the next time our class meets. Ah, the joys of majoring in pure unadulterated pain.

[@siekensou77]

ppl made calculators within Super Mario Maker. pretty neat stuff

[@zh84]

Very interesting and very clever. Also, if you make a straight line of dominoes and hold the one at the end vertical, then knock over the rest, if the bottoms of the dominoes don't slip as they fall over they end up approximating a curve called a tractrix.

[@linforcer]

I remember learning about half and full adders, but my mind just went straight to snakes. (vipers)

[@MrCooldude4172]

I always thought computer science was not for me. This video has truly amazed me. Thank you for posting this.

[@bno112300]

Now make a video about lambda calculus on computerphile, so people can complain that it should be here.

[@RtwikJoshi]

Lovely way to visualize two basic logic gates. This is why I love Numberphile

[@gibbytravis]

Here's how I do addition with dominoes... Let's say you want to add 2 + 3. Stand 2 dominoes in a line, then stand 3 more. Tip them over. If 5 dominoes fall down then the answer is 5. My method is superior.

[@sebastianzaczek]

I gotta try this

[@rujon288]

Ha

[@Thedaviddaly]

This is without doubt the best video I have seen on youtube in the 6 years I have been here. Wow this is the most elegant explanation of logic gates I have ever seen.

[@BenClayben]

Try making a NOR gate..

[@MysticalDork]

I love how he goes on about how crazy you'd have to be, all the preparation blah blah blah, "yeah, me and a couple of friends did this." XD

[@zubirhusein]

This is better than half the computerphile videos no offence brady

[@stephenkamenar]

how is that offensive? you just said half the computerphile videos are better than this. and this is fantastic!

[@wurttmapper2200]

Farzher Underrated

[@HalidYusein]

This is one of the greatest things I've ever seen! The video with the 10K dominoes is just brilliant as well!

[@GlobalWarmingSkeptic]

CHALLENGE: Create a NOT gate using dominos!

[@SeanFalloy]

Can I have +/- rails?

[@okaro6595]

Of course it cannot be created without an additional signal. If we have an additional signal comparable to a clock signal, then one can simply lead it to the output and use the input signal to block it.

[@SeanFalloy]

If this thing was clocked all the delay loops they use (also referring to the large one they built) would not be necessary.

[@trickytreyperfected1482]

Global Warming Skeptic Okay, what is your profile picture? I see this everywhere and I'm really curious as to what it is.

[@lorifairhead8124]

To add to my main comment I will say I liked the bit where you showed how one domino nearly fell and triggered a malfunction. A problem that could be very largely reduced near to zero with a, probably bigger, more sophisticated design. So reliability is a big issue as it is also in electrical circuits.

[@UnderscoreZeroLP]

I feel special because I already knew about most of these from redstone in Minecraft...

[@wigglespeedturbo6324]

***** Never understood how that was done till I saw this...

[@jordanjohnson714]

I feel special because I knew this before Minecraft

[@jonathanyang2359]

***** You can waste hundred of hours playing with little painted blocks or you can read a website for 15 minutes to learn the same thing. You choose.

[@UnderscoreZeroLP]

Jonathan Yang You're missing the point. The point was not that Minecraft was made to teach people logic gates and that it's a great way to learn them, the point was people think it's a useless game that's a complete waste of time when it really isn't.

[@cryoshakespeare4465]

***** What Jonathan Yang fails to appreciate about Minecraft is that is potentially an instrument of play that can nurture in children creativity, exploration, and a curiosity/excitement towards something like logic gates (through the redstone mechanic). Time for freedom/play is important for any individual, young and old (but especially young), and Minecraft is undoubtedly one of the better environments to do that in.

[@umcarainteressante]

WOW, this was amazing. Explains it in a very simple and consistent way.

[@Bigcubefan]

This video was mindblowing! Finally I understand this concept! :D

[@PerFnurt]

- Pick a number. - 42 - Of course.

[@papa515]

Beyond COOL!!!!

[@HaI0gen]

This is one of the best videos on Computerphile or Numberphile. It uses a simple mechanism that everyone intuitively understands in order to show how a complex machine is built from tiny parts. I love the bit of "domino engineering" that was used to make the AND and XOR gates work. The neat thing is that if you have enough dominoes, then you can build an adder of arbitrary size -- it is not merely an analogy of an adder; it *is* an adder. Wonderful visual and tactile illustration of the fact that a computer is not a magical box, nor is it something that can only be understood with advanced physics -- semiconductors are merely one of many ways to implement logic circuits, as are domino chains.

[@Eetarsaurus]

I would've liked to see a NOT gate.

[@thanawitsagulthang6471]

this is one of the best video I have seen so far from numberphile, KEEP UP WITH GOOD WORK!

[@LeventeLaczko]

Is it only me, being hipster, who played dominoes before redstone was cool?

[@leosax6962]

The domino computer is the most fascinating thing I've ever seen in my life.

[@thane732]

Alright, I'm using this same logic system to make a computer in "Minecraft Pocket Edition". For those of you who've played, you know that making a computer in "Minecraft PC" is possible, but only because redstone allows you to make clocks. However, in Pocket Edition, the only redstone alternative are signs that hold up sand, and are broken by the breaking of an original block of cactus. This is a one-time us signal transmitter, and therefore cannot be used to make a clock. However, it is theoretically possible to make an infinite amount of AND gates with signs, cacti, torches, and water. These gates can all be linked up to an infinitley large output display panel. Of course, since you can't sit down and work on an infinitley large computer, this computer will only be able to compute with a limited amount of numbers, and a limited amount of calculations. But hey, it's a start! I've already designed the AND gate. I'm not sure if I want to share the design yet (for fear of people stealing my idea,) but once I'm done, I may make a youtube video describing how to make it.

[@joeyhardin5903]

Are you done yet

[@bensons999]

That's cool that an xor is called 'Exclusive or'. A long (long!) time ago when I learned this stuff, (mostly by myself) I learned that xor= *X or* Y (but not both) I'm wondering- why did we need to change the lighting for the slow-mo camera?

[@RaaynML]

This helps with Redstone logic

[@drummyfish]

I once tried to make logic gates using cogwheels where CW rotation meant 1 and CCW rotation meant 0. I was even able to make flip-flop circuits (with additional tricks like shifting wheels) such as RS which are basicly a computer memory.

[@DudokX]

Yes new numberphile video! *looks at length :o OH YEAH!!

[@DeviousMalcontent2]

This is a really cool way of explaining logic gates.

[@winnerdoesroblox]

Still better than a Mac.

[@Samados99]

I saw logic gates in a neurobiology class last year to explain the inputs of inhibitory and excitatory neurons on a third output neuron. Just another particularly interesting application of this concept :)

[@crazybigyo]

Lol, cause 17 is between 20 & 50.

[@zZrEtRiBuTiOnZz]

I know, lol. I was gonna say the same thing.

[@j0h00]

I believe that for the half and full adder, a more common notation is A for input 1, B for input 2, CIn for input 3, and S for output 1, and COut for output 2. COut is connected to a CIn if you have multiple adders working together

[@Ral9284]

*Even knowing how logic circuits work before hand, this video still amazed me.* The most simple of things are the ones I found the most beautiful to contemplate. #BinaryCode #ComputerScience #LogicCircuit

[@josephdestaubin7426]

20 years I've been trying to understand computers on a fundimental level, and I think I finally do.

[@Prich038]

It's meant to be 0 0 0 1 1 0 1 1 You did it the wrong way around

[@aizenadante78]

1-1 2-10 3-11 4-100 5-101 6-110 7-111 8-1000 9-1001 10-1010 11-1011 12-1100 13-1101 14-1110 15-1111

[@aizenadante78]

16-10000 17-10001 18-10010

[@kiffe22]

i paused the video when he tried the second circuit. i thought of a solution and came up with the exact same solution that he did. never have i been so proud watching numberphile

[@keithwinget526]

This reminds me of all that time I spent doing this in Minecraft...for fun...

[@Explodenator]

This the most entertaining, enlightening, and thoroughly mind blowing video numberphile has posted in a while. Thanks a million for all that you do.

[@LB_]

Google Play lets you watch movies anywhere using Bananas in Mirrors, and computers do your math homework for you using Dominos in Videos.

[@js267]

This kinda blew my mind. Incredible. Why wasn't this published many years ago when I was first learning how computers work?

[@rogerdotlee]

I'm cool with this being on numberphile and not computerphile because binary has been around a LOT longer than computers.

[@Gerylovebg]

The look on his face says it all - he really enjoys doing this :) Thank you for making me smile, this is a great video!

[@ImaginaryHuman072889]

what would be really impressive is if you made a NOT gate - make the output domino fall over when no input domino is pressed :P

[@funicio]

An angle?

[@ImaginaryHuman072889]

Edwin Camuy no.

[@funicio]

ImaginaryHuman072889 Why? I can put some dominoes in a really long ramp, and there's an intersection with the part where the ramp meets the ground. In a way, if I press the input BEFORE the dominoes reach that spot, I'll stop them from reaching the output, creating a 0 output. Otherwise, if I leave it alone, the dominoes in the ramp will fall and I'll get a 1.

[@marctelfer6159]

Woah, I watch this video several times a year, and I've only just realised that Matt said "inatimate" instead of "inanimate". He was just so excited.

[@fy-]

Is it possible to make NOT gate with domino?

[@Gus-s9v]

Yes but complicated (what I mean is not normal)

[@Gnoccy]

Have you ever thought about this: The device you're watching this video on is literally an insanely complex halfadder explaining itself.

[@jennyjtg3022]

Java with dominos 👏👏👏👏👏👏

[@psow4062]

As an electronics engineer I must say that this is VERY COOL!

[@gustavmardby9364]

Im´m sure you´re going to love minecraft :P

[@SongSeeker7]

I remember trying to make an XOR gate before I saw this video. If you take a line of dominoes with 1 'breaker' that gives the expression C = (Anot) * (B). Using 2 of these and tying the 2 inputs together I get C = (Anot) * (B) + (A) * (Bnot) = A ( + ) B but I couldn't do it without having 1 path of dominoes needing to 'BRIDGE' over the other path. Its amazing how you figured out how to tie together 3 full adders with a 1/2 adder and not need any cross over bridges. Nice planning!