Colossus & Bletchley Park - Computerphile

[@russhellmy]

Another great video from Prof Brailsford. His presentation, enthusiasm and breadth of knowledge is infectious.

[@AdrianMulligan]

russhellmy Truly!

[@chicoknebel]

russhellmy Always a great addition to computerphile. More from him, please :)

[@AdrianMulligan]

I wish he was my uncle or something, I wish I had a teacher that had this passion!...I just wish more people could be like this!

[@ztoob8898]

Totally agree. He's a great teacher.

[@Triantalex]

false.

[@TheGrassyKnole]

Thank you for these wonderful docs. I was studing Computer Science at Queens Belfast in the mid 70's when this story really broke and we had to relearn all the history. We even had people who had worked with Turing fly in to tell us what really went on. Wonderful. The hard part was telling my Dad, who had been on the convoys, that the times they had it worst, i.e. he was getting torpedoed, was when they couldn't crack the Uboat codes. I think they thought they were all on their own. Great to be able share the story with him.

[@Triantalex]

ok?

[@CorneliusSneedley]

I love the videos with Professor Brailsford; he takes such joy in his work and never fails to make subjects that might otherwise seem quite dry very interesting.

[@Elround4]

Cornelius Sneed I agree, he also has a good voice. ^^

[@fdutrey]

Cornelius Sneed Such passionate person indeed. The kind of guy you could listen to for hours on end. Even as a layman.

[@ezragonzalez8936]

He is the David Attenborough of the computer world! Exact same passion and enthusiasm!

[@josephgaviota]

💯agree. I'd listen to this man read the telephone book.

[@Triantalex]

false.

[@stumbling]

I feel like we're due a trip to Germany to see the other side of the story and how the Enigma and Lorentz machines were created.

[@TheKyshu]

+CowLunch Yes! I'd be interested in that!

[@carbidegrd1]

Enigma was Swiss I beleive

[@Andyww08]

The Enigma machine was first patented around the mid twenties. It was created so that companies and banks could confer in secret. Despite it having a patent number, no one realised what it could be used for

[@sjpeckham1]

Lorenz....no T in the word. Just so no confusion with unrelated Lorentz transformations. Great video

[@Triantalex]

??

[@scottbrown6305]

I was once privilege to take a course given by a couple of gentlemen from GCHQ. What the BRITs did for the war effort behind closed doors is nothing less than phenomenal. This sort of video only hints at how really, really fantastic their efforts were.

[@doriphor]

Professor Brailsford is the most interesting person on the entire channel, I really wish there was more of him!

[@GuyWithAnAmazingHat]

As a general audience who's only knowledge on computer science came from this channel, this is the best and easiest to understand episode so far.

[@anotherdayisforever]

Prof Brailsford is a priceless resource. Thank you for your work and your service in the name of education sir.

[@Triantalex]

false.

[@pseudo880]

Tommy Flowers is an absolute legend. In my opinion, we don't hear enough about him because it doesn't suit the 'tortured genius' of narrative of Alan Turing. It was a team of people at Bletchley that did things. I don't know why we like 'lone wolf hero's' and we don't sing the praises of a team. For me, I rate Tommy Flowers as a total working class hero.

[@TheStevenWhiting]

Didn't Tommy essentially get ripped off as he ended up using his own money £1000 to build the machine to prove that it worked. They then gave him £1000 after but it still wasn't enough to cover the debts he'd got into due to building the machine. We have a film about Alan Turing, surely we should have one about Tommy Flowers.

[@Fennecbutt]

At least Tommy Flowers didn't suffer the hardships Alan had to, eventually leading to his suicide.

[@Valery0p5]

The thingy test? _that_ film should never be existed🤮🤮🤮🤮🤮🤮

[@malayagr]

@@Valery0p5 What are you talking about?

[@MrDaiseymay]

So typical of us Brits though isn't it. Hidden, forgoten hero, who had no just rewards. Had he been American, he'd have been a multi billionaire.

[@notgadot]

@@MrDaiseymay Most Yanks Are Poor..

[@robbiewilderspin9136]

Just caught up with this video. My Dad, as a 17 y/o apprentice at Dollis Hill, built some of the circuits used in Colussus. He didnt know what he was building and asked his boss who said ...just keep quiet and build it... I dont think he found out what he had contributed to until the late 40s

[@shortguy014]

I love videos with David in them, he always looks like he loves everything he is talking about!

[@Nerdthagoras]

Roflmuffin Yes a very positive gentleman indeed.

[@Triantalex]

false.

[@robinwells8879]

A wonderful piece of equipment that also served as a very effective heating system for the whole hut. I remember the warmth and wonderful smell. For clarity only a visitor and not a veteran operator. My loss! My guess is that the reward was working with a team of other extraordinarily talented people. Public recognition is nice but the experience of that team must have been extraordinarily wonderful.

[@ColinDyas]

I totally agree with the fact that the men involved in Lorenz should have received far greater recognition than they did. One even left the UK to further his research. Tutte was a genius. Flowers was not far behind him. In my very humble opinion they remain some of the UK's greatest unknown minds of the 20th century. They put in place the foundation of an industry that our nation never thought worthy of investment. Other nations grabbed the advantage and the rest is history. Sadly the same is true of other great UK inventors and technicians who also lacked the proper support. As such we lost out in several entrepreurial sectors that now define the modern world. The UK pathfinded the thinking. Others applied the commercial acumen. And I say this having worked for a company that commercilised interactive TV, yet no longer exists. Can we catch up? I doubt it. This is a great little film, about some truly great men.

[@stevedoubleu99B]

In 1987, I attended a BT overhead maintenance course at Bletchley Park. Along with the other trainees, I had no clue about the significance of the place, as at that time it was still a national secret!!!

[@elultimo102]

Around 1995 I saw a program in which they showed the Enigma, and demonstrated how it would change lights/letters, even when the same key was repeated. The feds had a fit, since it was still classified---50 years after the war.

[@leighedwards]

Please give full credit to Tony Sale and his team who did all the amazing hard work to investigate the original design and to fully rebuild it.

[@YingwuUsagiri]

Brailsford is possibly, if not probably the most interesting person on old tech. I still give Tom Scott my favourite all over but he's mostly doing these new tech videos which doesn't really make them comparable.

[@savavel]

Great video, really educational! I was there a couple of months ago, it was really enlightening in Bletchley Park, however the guy who maintained the Colossus was a bit grumpy in explaining how the machine worked. Professor Brailsford, added many interesting facts I didn't get from him. The professor is a joy to listen, wish I had him as lecturer in my uni. Keep the videos coming :)

[@scowell]

The Lorentz machines were used for many years by the Russians, the Italians, the Spanish, etc. It is to be assumed that there were Colossi in use for decades, even though Churchill demanded that they be broken into pieces "no larger than a man's fist". BP is on my bucket list! Thanks for the tour Professor Brailsford.

[@guy.h]

I think what was to become GCHQ took 2 of them

[@Lukeff7]

Love this. Bletchley Park/National Museum of Computing is one of my favourite places. I've been 3 times so far and will visit again some time I imagine. Highly reccomend.

[@EtzEchad]

When I got my computer science degree in 1977, this was all still secret. It came as quite a surprise that Eniac was not the first computer. Go Brits!

[@edwardtait4285]

Amazing. I´m just catching up with all this, three years ++ later but, boy is it worth it! Thank you.

[@dankswtf]

So glad I found this channel, this stuff is really fascinating!

[@AgnostosGnostos]

Tommy Flowers, the creator of Colossus first electronic computers died in 1998. Yes in 1998 long after the end of the Soviet era and during the expansion of internet in every home. It was a serious mistake that he wasn't Knighted. W. T. Tutte (Bill Tutte) died, another important person of the Colossus mentioned at 6:55 died even later in 2002 and wasn't knighted either.

[@mellowfish316]

It is wild to think that this machine was still classified when I was learning to program as a child. I was reading books on programming and they talked about the "first" computer being ENIAC (as mentioned in this video), and nobody had any idea otherwise.

[@Roxor128]

You've really got the right idea with regards to computing history up there in Britain, with the building of functional replicas of historical machines. I wish we'd do the same for CSIRAC down here in Australia. The original is on display in a museum in Victoria, but they can't get it working again without changing it too much.

[@SardiPax]

I think Tommy was also from the wrong part of society to be given the recognition he deserved. Unfortunately it's a common story for Engineers in the UK, even today.

[@DrRawley]

Sardi Pax He should have invited the higher-ups over for tea from his Royal Doulton china set.

[@TheThorns]

Not just the UK, that happens to engineers everywhere.

[@CarlsTechShed]

Yes, even today most engineers are bound by non-disclosure and non-compete agreements, so they can't even mention on their CV (Resume) what they have achieved. They can say they worked as an engineer for Cisco or Alcatel for so many years but as soon as prospective employers want to know exactly what they've done, they just have to say "I'm sorry, I'm under an NDA".

[@jwadaow]

@@CarlsTechShed maybe they are testing the engineer's adherence to the NDA before considering their employment.

[@Triantalex]

??

[@johnmartin6178]

I went to BP about 6 years ago and saw the Colossus working, well a demo that is, when it was part of the BP experience and not a separate entity in the Computer Museum. After the talk we were given a bit of paper tape and asked to decrypt it. Well it was a straight forward Boudot message which said Hello From Colossus, but it's taken me 6 years to get around to sorting it out. Just as well they were a bit quicker in '44?

[@amberfranklinmk93]

I love the sound that the machines like the bombe, the which and the colossus make. I find the sound calming.

[@unvergebeneid]

I'm not from North America, I've never heard the word "thermionic valve" ... but I do think it sounds awesomely steampunk.

[@douggwyn9656]

Penny Lane "Thermionic valve" is British for what Americans usually called "vacuum tubes".

[@unvergebeneid]

Doug Gwyn I had obviously looked it up but thanks :)

[@NoriMori1992]

+Penny Lane I had a similar thought! To me it sounds like a term you'd see in an Asimov robot story!

[@unvergebeneid]

@@foobarmaximus3506 wow, inferiority complex much?

[@richardsinger01]

@@foobarmaximus3506 Just occasionally you have to accept that someone else got there before you. The thermionic valve was invented by John Fleming in 1904 - he was an English physicist. The term used for his invention was the thermionic valve. The name stuck in the UK. This is not a nationalistic thing, believe it or not. Lee de Forrest developed Fleming’s thermionic valve, thus inventing the triode in 1906. He was of course an American.

[@tomvanbreukelen2909]

Wow, this is so incredibly interesting. I love Prof Brailsford videos.

[@charlesmiller000]

Thank you ever so much Professor Brailsford for your 2-part Enigma series and, as icing on the cake, this Colossus video. Brilliant. (but wait, there's more?!)

[@Hyporama]

1:04 "one thing that was very difficult was to get them to have memory, because memory (for computers) hadn't been invented"

[@Horrigmo]

Another amazing channel to subscribe to. What a time to be alive!

[@sjmww1235]

thanks for filming this. I got to go to bletchly but only managed to see about 1/4 of waht was there.

[@Aamnah]

I always appreciate him explaining thermionic valves to non-UK folks

[@stuartthegrant]

Good to see Tommy Flowers get some overdue credit.

[@Triantalex]

??

[@electricadventures]

A wonderful piece of computing history, very enjoyable video as well, thank you.

[@msimon6808]

Valves also last longer if you reduce their plate and filament voltages. There are minimums and you probably need to test the valves that actually go into the machines. In America we call valves ==> tubes. I started repairing tube TVs in 1957.

[@Volcano-Man]

The Colossus rebuild came first - I was involved in it. Then came all the other computers showing how they evolved from Colossus.

[@Nilguiri]

Those high speed paper tapes are amazing! I had no idea.

[@scowell]

Optical technology, lots of new science in them. Synced to the sprocket holes, with no sprockets of course.

[@Triantalex]

??

[@Nilguiri]

​@@Triantalex Which part are you having difficulty in understanding? He talks about the high-speed paper tapes at 1:10. Cheers.

[@bikutoso]

This is one more reason for me to wanting to go to Bletchley Park.

[@AlanCanon2222]

Please do that if you can, I did in 2003 and it was the most moving site of those I visited in England.

[@voidshell6273]

"Flowers, what have you done ?!" Instant goosebumps here ...

[@SirReptitious]

Seeing as the people working at Bletchley Park were very smart, I presume they knew that their work would be kept secret even after the war. Hopefully they were satisfied and found fulfillment in being ESSENTIAL to winning the war. I also hope that the govt found other ways of compensating them; ie. monetary bonuses! A big check sure can take the pain away of not being knighted I dare say. ;-) I am American, so I don't know as much about what the UK did in the war compared to the US of course. But I DO know that there is no way any of the Allies could have done it alone!

[@sbalogh53]

0:11 Wow. I have one of those core memory stacks in a box under my bed. I could never bring myself to throw it out. I also have a few boards similar to the one behind the stack.

[@BorysPomianek]

I used to love to play with this type of tape when I was a kid - something about its engineered quality really appealed to me.

[@JonCape]

Nice to see Phil working on it

[@comochinganconesto]

I love computerphile, Professor Brailsford truly is the best on this channel (sorry everyone else y'all rock too). Does he still teacher? If so, I might take a sabbatical to the UK just to sign up for one of his classes... hell I'll even settle for siting in on one of his lectures.

[@mopokebonza729]

Wonderfully interesting presentation.. thank you so much

[@HackingVision]

Very nice video I watched the movie about bletchley park the imitation game thanks prof brailsford.

[@007bistromath]

I don't have time to watch the video right this second, but I just want to say the thumbnail is amazing. It looks like Prof. Brailsford is some kind of IT Willy Wonka.

[@HazelTheHare]

Went there not long ago. Sucks I missed you, would have been cool to see the filming of a computerphile video

[@avro549B]

It would be nice if the titles of these videos included a sequence number, since some of them will make more sense viewed in order.

[@Triantalex]

??

[@James_Bowie]

"What type of glue is Pritt Stick? Water, potato starch, and sugar: what reads like an ingredients list for baked- goods are actually the main ingredients in Pritt glue sticks. Up to 90 percent (including water) of a Pritt glue stick is composed of natural ingredients. The original Pritt glue sticks and all-purpose adhesives are solvent and PVC-free."

[@NoriMori1992]

"Thermionic tube" sounds like a sci-fi term you'd see in an Asimov story.

[@porridgeandprunes]

No, it's "thermionic valve" (English) and "vacuum tube" (American).

[@NoriMori1992]

Yipyap First of all, "thermionic tube" is an equally valid term. Second of all, even if it wasn't, that wouldn't have any bearing on my comment, which states only that it sounds like a sci-fi term you'd see in an Asimov story, which is true regardless of whether it's the correct term or not.

[@Triantalex]

false.

[@HighlanderGeoff]

Americans regard the Atansoff/ Berry Computer to be the first electronic computer. It used a binary system to analyse mathematical equations while, I believe, the Colossus used a decimal system and was limited to the analysis of alphabetical letters (words).

[@profdaveb6384]

Bundy Yes - you probably noticed that I kept saying things like "arguably" and "one of" quite a lot! Sean has now adjusted the first sentence on the Info page along these lines. Wikipedia has a page on the Atanasoff - Berry computer (ABC) that summarizes things very well. I hadn't realized that ENIACs patents had been declared invalid as a result of US Patent Office finding out about ABC. The computer historians seem to think Colossus was more "programmable" in some sense than ABC and certainly had more valves (!) But one thing we all apparently agree on was that ENIAC wasn't the first .....

[@DutchPhlogiston]

Extremely interesting! Thank you. I especially enjoy how he places the achievement of designing/building this machine in its historical context. I think it would be very interesting to see a video one day on the process of how the cypher was cracked. Does the fact that the tape has 5 holes imply that this machines CPU and bytes are 5-bit?

[@dt21467]

I love Bletchley Park; great place!

[@MrDaiseymay]

Great Mansion, many riddiculed it's lack of form and grace, as though bits added on were an afterthought. I love that. AND, it's uniqueness. Now, recognised around the world.

[@MrKen-wy5dk]

I'd like to see a video on the history of Japanese code machines and their developers.

[@RobinWootton]

Thanks to their unsung calm under existential pressure - we are here today.

[@letsgocamping88]

Love a brailsford video

[@peterlamont647]

Me too. He has such a great personality and way about him that draws you in.

[@josephgaviota]

It _is_ hard for us to imagine a time when "memory" wasn't readily available. We're _so_ accustomed to writing this or that to a memory location.

[@leogama3422]

*Wasn't available at all! They had the equivalent of 'registers'. But memory? Code? You programed the hardware itself.

[@MrJohn1966elliott]

Wow !! Big Old Computer !! I love it

[@the-chillian]

But ENIAC _wasn't_ a special-purpose computer. It was a general purpose computer capable of solving any class of arithmetic problem. While computation of gunnery tables was the excuse to get it funded, the first problems it was actually given to solve were related to the Manhattan Project. ENIAC was in operation from 1945 to 1955. If all it was going in that time was computing gunnery tables, it would have been a bit of a waste.

[@NathanSempiedade]

I'm planning on visiting bletchley when I travel to the UK in a few months... Can someone please tell me if 5 hours is enough time to visit Bletchley Park and the Museum of Computing?

[@fortboy66]

The breaking of Enigma and the teleprinter codes was not mentioned once on that great TV program with the voice of Lawrence olivier, The world at war, because it was still secret in the early 70's?

[@alexhayden2303]

My uncle worked with Tommy Flowers at Dollis Hill. Unfortunately I was too young to understand what that meant. He never spoke about his work, I understood he worked for th GPO, as did his brothers.

[@stensoft]

The important question is: has anyone ported Doom to Colossus?

[@vlad-j4m]

asking the reel question.

[@Amethyst_Friend]

This was before Doom.

[@ACHEESEDANISHZ]

@@Amethyst_Friend woosh

[@JonathanOsborneAU]

Will it run Crysis?

[@leogama3422]

It only run Hitler's doomsday

[@MrDaiseymay]

Apparently, WE, didn't reveal to Germany, the Colossuss, and goings on at Bletchley during the war, until the late 1970's. when they joined N.A.T.O.

[@RobertasJasmontasInsane]

This should have had title saying "the computer before ENIAC" or something similar then it would get loads of views. I was really suprised to hear that it was 2 years before ENIAC, good job, keep it up!

[@keithrobinson5752]

Flowers suffered in part because of socal background , lack of Oxbirdge education and that those that do are regarding as lesser to those that think. He was treated as a mere 'workman ' doing his job under the orders of superiors, and so his ideas where merely a product of that system not to be given the status of people such as Turning .

[@BunnyFett]

Love this.

[@williamgeorgefraser]

Civil servants wanted to keep knighthoods for themselves.

[@lovecastle7154]

Brilliant video

[@ihrbekommtmeinenrichtigennamen]

Geez, that tape though! 5 Bits per Character * 5000 Characters per Second = 25000 Bits per second 25kBit/s is almost half of the early DSL speed.

[@DFPercush]

Ihrbekommtmeinen Richtigennamennicht That was dial up, but yeah that's pretty amazing. And yet, in the 70's there were teletype terminals that ran at 110 baud, or 110 bits per second.

[@stumbling]

Ihrbekommtmeinen Richtigennamennicht FYI bits is with a lowercase b, bytes is uppercase, i.e. kb (kilobit), kB (kilobyte).

[@ihrbekommtmeinenrichtigennamen]

CowLunch Can you point me to some official documents on the matter? Because I have seen all sorts of combinations. kb, kbit, kbits, kbyte, kbytes and in all combinations of capitalization.

[@stumbling]

Ihrbekommtmeinen Richtigennamennicht "The symbol for bit, as a unit of information, is either simply bit (recommended by the ISO/IEC standard 80000-13 (2008)) or lowercase b (recommended by the IEEE 1541 Standard (2002))." - Wikipedia

[@ihrbekommtmeinenrichtigennamen]

Ok, that makes sense. Thanks.

[@warnford]

7:00 the civil servants said - we can't go around knighting all these people - so instead we will knight ourselves ! and give ourselves the awards they deserved so much

[@vtownhood]

So I know these machines were used to decode encrypted German communications but how though? Did they plug radios up to them or did people manually input the communications they intercepted?

[@scowell]

There were corps of radio listeners feeding this effort. There were many different radio links using 'tunny', or 'tuna' as we would say in USA.... the different encryptions had fishy code names, 'sturgeon', etc. The received radio was turned into TTY tape, which was then run on Colossus. There's an excellent book, now in paperback... I'm just finishing my second read through it, it's very engaging and not too technical... look up Colossus on Amazon.

[@tony00165]

Britain had stations all over the world listening in to international and battlefielf transmissions which were passed back to Blethchley Park and even at the outbreak of WW1 within hours a British ship went out to lift the transatlantic telephone cable off the sea bed to intercept messages....Who else would have thought to do that....only the British.

[@josephgaviota]

I wonder why the distinction of "thermionic valves" vs "vacuum tubes." I grew up with "tubes," in the radio and TV (Telly), and knew "valves" as those round things in internal combustion engines.

[@GegoXaren]

Also, ENIAC was not the first American computer... It was based on the Atanasoff-Berry computer (The ABC). The ABC was not based of the Colossus. The ABC is dated to "March 1939" if I read the wikipedia article correctly.

[@Ts6451]

***** I guess the issue is really all down to what requirements you choose when defining the term "computer". Something like the Antikythera mechanism could be a computer if you are just using a wide enough definition.

[@GegoXaren]

Ts6451 Indeed... I would not call eighter of these computers, they are not Turing Compatible (are they?) The Radix/Tabulating machine (1890) could be called the first computer too if ther can be single purpose, and the Automatic Looms...

[@mojosbigsticks]

Well worth a visit, but you'll need the whole day.

[@martin-xq7te]

Yes Tommy Flowers a great engineer about time he gets a mention

[@dbcooper7326]

He wan't Oxbridge educated, so irrelevant according to the nobility.

[@the123king]

It's a beautiful machine. If you ever get the chance, go see it.

[@techtipsuk]

Fascinating.

[@granskare]

the "bombe" was from the Polish. Tommy Flowers was a special guy.

[@VelMa-opinion]

Churchill most likely couldn't imagine how much, how quickly, computers would advance after the semiconductor technology allowed cheap low voltage transistors. So he thought that the (then in his mind inevitable) coming war with the Soviet Union would also be up to a Colossus.

[@MidnightAmratha]

Now that the secret has been declassified, why not make a official announcement about who buildt the first computer, their names deserve to be celebrated.

[@auntiecarol]

Mwah! Pritt Stick... haven't since one of those since I left primary school over thirty years ago.

[@dmcg7900]

I could watch that man walk around BP for hours

[@Andyww08]

There are things that Colossus was used for, are still secret even now

[@jasonwangtw]

Our school showed this!

[@soviut]

I had a hunch when I heard it but "pritt stick" is what most people in North America call a "glue stick", Pritt being a brand name.

[@CallumAi]

soviut Pritt's also German. Little bit of irony there.

[@ktxed]

Prof. Brailsford totally works for GCHQ :D

[@GoSlash27]

6:30 Correction: The ENIAC was the first general purpose fully programmable computer. They used it to calculate artillery tables in the early days, but it wasn't limited to that application and was used for many others. COLOSSUS was a breakthrough achievement in its own right, but wasn't in the same category as ENIAC. Both are historic firsts.

[@MrDaiseymay]

In another video on YT, a gathering of international Computer experts ,in California, Headed by a Top professor on the history of computer's said. The Americans were astonished in 1946, when they were told of Collossus, and it's part in the War, especially as it emerged 2 yrs before the Eniac, ''WHICH WAS NOT PROGRAMMABLE, WITHOUT VIRTUALLY DISMANTLING IT , AND REWIRING IT, TAKING 3-4 HOURS.''

[@leogama3422]

Yes, but I think the distinction is small. Colossus was the first electronic, programamable, digital computer, but it was made special purpose because they needed it to be so for speed. Maybe they could have built a general purpose computer if there was a need. Who knows? If Mauchly and Eckert must be remembered for anything, what really performed the next step forward was EDVAC with stored programs.

[@DavidDavies-f4v]

What Nonsense COLOSSUS designed and built by TOMMY FLOWERS it was the first and it was reliable it didnt keep breaking down

[@BEP0]

Nice

[@MystMagus]

I guess the idea of keeping the whole thing secret basically indefinitely makes some sense if you have no real reason to believe that relatively soon technology is going to be invented that will be so much better than valves that it's pretty much incomparable. If you expect that things will have to remain as large scale as things had to be then, it makes sense.

[@Orxenhorf]

***** Can you do a video explaining how vacuum tubes work?

[@eiclanlan2854]

Gday mate, I can give you a basic explanation. There are mant youtube videos btw. The tube has two plates and a heater. One plate is the anode but is called "the plate" the other is the cathode and given the letter K to describe it. The early tubes has the two plates. Power caused electrons to flow from cathode to anode producing an amplification. Then it was discovered that if a grid was placed between the anode and cathode much more amplification was produced . Sorry for avery inexpert explanation. There are many videos that will do it better than me. Cheers Ross

[@MrDaiseymay]

Just look at it though, and try and imagine how the average person would have comprehended it's purpose, let alone how it worked

[@Divine_Evil]

Video on the ABC computer?! Please!

[@goeiecool9999]

0:40 wait is that guy part of the expo?.... Oh nvm he moved.

[@packlimo]

I went there last week :D