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

His famous words: I may have done this

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!

I love it. Brilliant demonstration of logic gates.

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

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.

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!

Now build a NOT gate with dominos.

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

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.

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

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

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

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

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

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

More like "Domino Addiction".

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!

"Disproportionally excited"

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!

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

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.

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.

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

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

Somebody needs to show this guy Minecraft.

redstone! anyone?...

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!

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

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.

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.

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

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

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

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

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

I do all my calculations via dominos

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

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.

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

I wish Matt would write a book about Domino computing

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

*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.

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

ppl made calculators within Super Mario Maker. pretty neat stuff

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

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.

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.

Try making a NOR gate..

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

One of the best Numberphile videos I've seen yet. Well done Brady.

this is by far the best video I've ever seen in numberphile

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

Beyond COOL!!!!

utterly brilliant. maths, computing and a bit of geeky fun. ticks all of my boxes. best video i've ever seen on youtube!

The amount of patience one needs to built such things is really overwhelming ! Too good !

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

I would've liked to see a NOT gate.

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

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

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

This is better than half the computerphile videos no offence brady

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.

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.

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

CHALLENGE: Create a NOT gate using dominos!

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

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

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

This helps with Redstone logic

I love his enthusiasm, it s infectious

Hands down the best video ever on numberphile.

Lol, cause 17 is between 20 & 50.

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.

- Pick a number. - 42 - Of course.

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.

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.

Still better than a Mac.

I've been looking for this forever! Love "I only interact with the terminal" Lol, that's still the software layer on some level.

This was very enjoyable! I would love to see more of these domino videos!

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

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

This should probably be a Computerphile video but it's still awesome here too.

To me this is the most relevant video on youtube. I just found out the answer to one of the most intriguing questions I ever posed myself.

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

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

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

I'm dying watching your hand hover around the dominos

*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

Is it possible to make NOT gate with domino?

HAHA! I've never seen a numberphiler having so much fun (and so pleased with his creation) as Matt. And he's right, this is what i've always wanted to know about how computers work. Good Job!

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

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

Java with dominos 👏👏👏👏👏👏

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

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

Just dont show him what Minecraft is :)

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

I've learnt this in my first year as a student studying IT, but I have to say that this is a superb illustration and I wish this video was included in the teaching materials. Would've made things so much easier to understand

the fact that Matt wrote the input in this order: 00 10 01 11 instead of 00 01 10 11 drives me insane!