“Why are manhole covers round” is one of the eternal questions in job interviews, and so it seems to be at Microsoft. The desired and politically correct answer to the question is: “Manhole covers are round because round is the only shape that can never fall into the manhole and hurt someone (with the hole of the same shape, but slightly smaller size than the cover)”. And the answer is wrong.
Let’s ask Mr Feynman:
“Interviewer: Now comes the part of the interview where we ask a question to test your creative thinking ability. Don’t think too hard about it, just apply everyday common sense, and describe your reasoning process. Here’s the question: Why are manhole covers round?
Feynman: They’re not. Some manhole covers are square. It’s true that there are SOME round ones, but I’ve seen square ones, and rectangular ones.
Interviewer: But just considering the round ones, why are they round?
Feynman: If we are just considering the round ones, then they are round by definition. That statement is a tautology.
Interviewer: I mean, why are there round ones at all? Is there some particular value to having round ones?
Feynman: Yes. Round covers are used when the hole they are covering up is also round. It’s simplest to cover a round hole with a round cover.
Interviewer: Can you think of a property of round covers that gives them an advantage over square ones?
Feynman: We have to look at what is under the cover to answer that question. The hole below the cover is round because a cylinder is the strongest shape against the compression of the earth around it. Also, the term “manhole” implies a passage big enough for a man, and a human being climbing down a ladder is roughly circular in cross-section. So a cylindrical pipe is the natural shape for manholes. The covers are simply the shape needed to cover up a cylinder.
Interviewer: Do you believe there is a safety issue? I mean, couldn’t square covers fall into the hole and hurt someone?
Feynman: Not likely. Square covers are sometimes used on prefabricated vaults where the access passage is also square. The cover is larger than the passage, and sits on a ledge that supports it along the entire perimeter. The covers are usually made of solid metal and are very heavy. Let’s assume a two-foot square opening and a ledge width of 1-1/2 inches. In order to get it to fall in, you would have to lift one side of the cover, then rotate it 30 degrees so that the cover would clear the ledge, and then tilt the cover up nearly 45 degrees from horizontal before the center of gravity would shift enough for it to fall in. Yes, it’s possible, but very unlikely. The people authorized to open manhole covers could easily be trained to do it safely. Applying common engineering sense, the shape of a manhole cover is entirely determined by the shape of the opening it is intended to cover.
Interviewer (troubled): Excuse me a moment; I have to discuss something with my management team. (Leaves room.)
(Interviewer returns after 10 minutes)
Interviewer: We are going to recommend you for immediate hiring into the marketing department.”
Giving an otherwise rather dull and predictable keynote speech at Infosecurity Europe about the IT security demands of running the London Olympics, Derek Wyatt MP has let it slip that UK Government hands are tied when it comes to security technology. He also made it clear that he has no idea where the security threat will come from stating “who are the enemy? I wish I knew” and “don’t ever underestimate the intelligence of the opposition, whoever that is.” But the biggest concern I have over the ramblings of the Right Honourable gentleman came when he started talking about the problems faced in identity management and authentication not only during the event but in the run up to it, with the construction of the venue. Wyatt sound quite upbeat about the possibility of using the London ‘Oyster’ card, used for public transport travel, which could be upgraded fairly easily to incorporate biometric data and turned into a mini-ID card. He also sounded quite impressed with the idea of using the Nokia based authentication system for mobile phones. Upbeat and impressed, and then he dropped the bombshell, which I hope will not be a bad choice of words for the future, when he casually revealed that because neither of these companies was a ‘major sponsor’ of the Olympics their technology could not be used.
Yes, you read that right, as far as the technology behind the security of the London Olympic Games is concerned best of breed and suitability for purpose do not come into, paying a large amount of money to the International Olympic Committee does.
Even when questioned by a member of the British Computer Society Security Group who was as shocked as I, and expressed total disbelief that potentially far better technologies were to be overlooked simply because a sponsor had to be used, Wyatt gave a half-hearted shrug of the shoulders response along the lines of it is out of our hands.
Feel safer yet?
Google was ranked by Fortune magazine as the best place in the US to work, and it has reached another zenith by becoming the most popular Web site. It’s even become a verb in the dictionary.
And it may even have started a new trend by creating a job that carries the title “chief culture officer.” Stacy Savides Sullivan is that person at Google.
What do you do as chief culture officer?
Sullivan: I work with employees around the world to figure out ways to maintain and enhance and develop our culture and how to keep the core values we had in the very beginning — a flat organisation, a lack of hierarchy, a collaborative environment — to keep these as we continue to grow and spread them and filtrate them into our new offices around the world.
A “lack of hierarchy” as a key phrase in their culture, and yet she’s “chief culture officer”.
So Google is just like any other company with a “do as a say, not as I do”. Either that, or she’s a native american.
BILL MOYERS: Well, what is your thinking about why it is as– the war enters its fifth year, and the President has announced – an extension of tours to 15 months, and they’re going to call up the National Guard. And April was the bloodiest month so far since the war started, and there was one day in April that was the bloodiest day. That people have seen they have no way to get the guys in Washington, and Condoleezza Rice, to listen to them. That there seems a detachment emotionally, and politically in this country from what is happening.
JON STEWART: You know, one of the things that I do think government counts on is that people are busy. And it’s very difficult to mobilize a busy and relatively affluent country, unless it’s over really crucial– you know, foundational issues. That come sort of sort of a tipping point.
BILL MOYERS: War? War?
JON STEWART: But war that hasn’t affected us here, in the way that you would imagine a five-year war would affect a country. I think that’s why they’re so really – here’s the disconnect. It’s sort of this odd and I’ve always had this problem with the rationality of it. That the President says, “We are in the fight for a way of life. This is the greatest battle of our generation, and of the generations to come. “And, so what I’m going to do is you know, Iraq has to be won, or our way of life ends, and our children and our children’s children all suffer. So, what I’m gonna do is send 10,000 more troops to Baghdad.”
So, there’s a disconnect there between – you’re telling me this is fight of our generation, and you’re going to increase troops by 10 percent. And that’s gonna do it. I’m sure what he would like to do is send 400,000 more troops there, but he can’t, because he doesn’t have them. And the way to get that would be to institute a draft. And the minute you do that, suddenly the country’s not so damn busy anymore. And then they really fight back, and then the whole thing falls apart. So, they have a really delicate balance to walk between keeping us relatively fearful, but not so fearful that we stop what we’re doing and really examine how it is that they’ve been waging this.
A speeding tanker truck with 8,600 gallons of gasoline slammed into a guard rail near the Bay Bridge early today, sparking an explosion and intense fire that collapsed the ramp from eastbound Interstate 80 to eastbound Interstate 580, the California Highway Patrol said.
Portions of the heavily traveled MacArthur Maze will be closed for weeks, if not months, causing the worst traffic disruption in the Bay Area for commuters since the 1989 Loma Prieta earthquake.
CHP officer Trent Cross said the driver of the tanker truck crawled out of the passenger window, walked down the ramp to a gas station and took a taxi to a nearby hospital.
More pictures here