 What's up everybody? How are y'all doing? So we're nearly done. Hope everybody's had a fantastic RubyConf. Hope you've all enjoyed all of the talks you've seen, all the wonderful people you have met. I actually have something I would like to ask your help with real quick before we get started. It was my son's birthday this week and I wanted to see if you would be so kind as to help me tell him happy birthday. So on the count of three I would be forever indebted if you would all say happy birthday Holden. One, two, three. Thank y'all. Y'all just blew his mind. He's watching it home on the live stream. So thanks for your help on that. So some of you have seen me speak before but for those of you that haven't, I'm a storyteller, not a normal conference speaker. I really like telling stories of failure and redemption and this is one of my favorite stories. This is the story of a structural engineer named Bill LeMezier in a building in New York that was built on stilts. Our story starts in the 1970s and I'm sure most of us in this room don't remember America in the 1970s but we were in the midst of an economic recession. We had just come out of Vietnam and it's been a ton of money on that war. There was an oil embargo that was causing runaway inflation and because of that our country was running out of money and so were our cities. This picture of the New York subway is pretty representative of what public infrastructure in the 1970s looked like in New York. They were so close to bankruptcy they didn't even have the money to go and clean up the graffiti in the subway. And the city might have gone bankrupt had it not been for this man, Walter Riston. Now Riston is a businessman but he's also very civically minded and in the 1970s seeing his beloved New York on the verge of bankruptcy he went to the New York legislature and he encouraged them to create this thing called municipal assistance corporations and what max were where these corporations cities could set up that could sell bonds to finance their ongoing operations during times of financial crisis. So he helped the city of New York get that to the New York legislature and then he went and tried to sell those bonds to people in New York. He went around to the big banks into the big Union pension funds trying to sell them and it helped that he was the CEO of one of the banks that was buying up a lot of these bonds. The first national city bank of New York. Now you've all heard of this bank but you may not know it because they changed their name in the 1970s to Citibank. Now 1970s Citibank was actually sitting in pretty good shape and despite the recession they had diversified their investment portfolio they had spread out their loan portfolio they still had plenty of money on hand they weren't hurting. The only problem they really had was that they were out of room at their headquarters at 399 Park Avenue. Now if you or I had encountered this problem we would have gone to the building next door and leased a couple of floors there and been happy with that answer but you and I are not Walter Riston. Walter Riston wanted to make two statements. Number one he wanted to show everybody that the city of New York was still in or that City Corp was still in great shape despite this recession they still had plenty of money and second he wanted to show City Corp's commitment to the city of New York. Despite this recession City Corp was there to stay and when you're a man with ambitions the size of Walter Riston the best way that you can think of to do this is to build a signature skyscraper on the New York skyline because you need a couple floors of extra space right and so they started up buying up property a whole city block in fact their headquarters are at 399 Park and they started buying the block right across from them but they ran into a problem. The good people of St. Peter's Evangelical Lutheran Church liked their church right where they had it and where they had it was right here at the corner of 54th in Lexington right on the prime corner of City Corp's block. Now City Corp owned all the rest of the land on this block the only holdout left was St. Peter's and they knew exactly how strong their hand was and they decided to play that hand so they went to City Corp and said well yeah we'll sell you our land but you have to build us a new church and City Corp said well sure we can build you a new church where do you want it? Right where it is. Well they didn't really have an option. St. Peter's wasn't compromising on their demands there wasn't enough money to make them move anywhere and so they had to figure out how to build this church on the corner of their lot and still build this signature skyscraper that they wanted to build. So Walter Riston went to this man Hugh Stubbins his architect for the project and said Hugh here's the deal we've got this church that's not moving it's got to be on the corner of the lot not only that but they've said we can't have any support structures going through the church we can't have any adjoining walls with the church it has to be a freestanding structure but we can build over the church. This was actually the first air rights transaction in New York real estate history it's pretty common now. So Stubbins had an idea he thought maybe they could cantilever the corner of the building over the church and he brought his structural engineer in to consult on this to see if it might be possible. I mean named William LeMesure and so Stubbins tells Bill his idea and Bill says well sure I imagine we can we can figure that out we can cantilever one corner and Stubbins thinks about it a little bit and he says well you know what it would be really nice if we cantilever two corners of this building and make for some nice symmetry if we did that and LeMesure said well that's going to be harder but I'm sure I can come up with a plan where we can do that. Then Stubbins got greedy he went to LeMesure and said Bill we could build this building with a ton of open space at the bottom the base would be ridiculously dramatic if we just cantilevered all four corners and so that's just what they did. You can see St. Peter's Church tucked under one corner of the building and the building itself is set up 10 stories on those skinny little columns. Now it doesn't look like those columns would be enough to support that giant building but that was the genius of Bill LeMesure's design. Like most really great ideas this one came about in the form of a napkin sketch. Bill LeMesure was sitting at his favorite Greek restaurant next to his office in Cambridge, Massachusetts when he had this idea for these triangular braces down the side of the building. Let me explain how this works. Now in most buildings the bulk of the structural load is carried by columns going down the corners of the building. Those are the strongest part of the building but what happens to that load when the columns don't go all the way to the ground? This was the problem Bill LeMesure had to solve. How to support the building when he didn't have the normal weight bearing members to support it? So you can kind of see the start of his design on this napkin sketch. He's got these triangular braces running down the side of the building to direct the load to the columns at the base. Explain a little more about how this works. There's six triangular chevron braces each eight stories tall that go down the side of City Corp Center. Let's take this floor right in the middle of one of those chevrons. The load from that floor goes down the corners and the center of the building to the chevron right below and that chevron directs the load to that center column where it goes to the ground. That's how it handles structural load. That's how it handles the weight of the building itself. But there's also a wind load. So at the top of the building wind can sometimes get high enough that it overcomes the compression strength of the building. Literally the weight of the building is what holds it together in the face of the wind. But at the top of the building sometimes there's enough leverage that goes beyond that compression strength. So these angular braces take that wind load on the face of the building and transfer it down to that central column and down to the ground. It was a genius design. So LeMessure took his design to the New York City Department of Buildings and they decided that it was structurally sable and could go forward with construction. And so final plans were drawn up and construction began. Now Bill LeMessure self-confessedly is an egotistical man and he tried to convince Hugh Stubbins that these structural braces should be on the outside of the building where everybody could see them. But Stubbins was set on having a sleek glass and aluminum facade and he wouldn't agree to do this. So this is one of the last pictures where you can actually see these chevron braces in their entirety when the building is under construction. I don't know about y'all but that doesn't look like a lot of steel to me. And the reason it doesn't look like a lot of steel is because it's not. The steel structure of this building weighs somewhere on the order of 25,000 tons. And to give you a basis of comparison the Empire State Building just a little taller than City Corp. Center weighs 60,000 tons. So over twice as much. So by reducing the weight that dramatically that's what allowed this building to be built up on these 10-story tall stilts. But it had the side effect that because the building was so much lighter it didn't have a lot of resistance to the wind. This building liked to sway. Now you may or may not know this but all tall buildings sway to some degree. It's actually much stronger to build a building that has some give to it and can sway in the wind than a rigid building. The wind would blow a rigid building over. The problem comes in when you put humans in the building. You could actually allow a building to sway pretty considerably and it would still be structurally stable but as it turns out humans don't like that very much. If you and I were on the 59th story of City Corp. Center in the middle of a windstorm we would probably be disconcerted by the building moving under us and we would quickly get seasick because our eyes would not be able to reconcile the motion that our bodies were feeling. And so in order to build a building with such a light steel skeleton build a measure installed the first tuned mass damper in a skyscraper in North America. Now in this case it's a 410 ton block of concrete you can see it at the top of the screen there floating on a very thin film of oil and this tuned mass damper counteracts the effects of the wind on the building. It reduces sway by about half and it's easier for me to show you how this thing works. So here's what it looks like in action. You can see that concrete block moving back and forth very subtly but the interesting thing about it is the concrete block is the most stable thing in this picture. The building is actually moving around the tuned mass damper and as the building moves out from under this 410 ton block of concrete it shifts the center of balance of the building ever so slightly and reduces the amount that the wind is making the building move by about half. And as the building oscillates back and forth it stops that motion much more quickly than if the tuned mass damper wasn't there. It was one more amazing innovation in this building. When it was completed City Corp Center was the seventh tallest building in the world at 914 feet and 59 stories tall. It was positively received the New York Times said that Stubbins had created one of New York's significant buildings and if you've ever flown into New York City the bright silver angled top of this building is always easy to spot in New York skyline. But Stubbins wasn't the only one getting praise. Bill LeMessur received wide acclaim for his structural innovation in this building. It was actually named a fellow of the National Academy of Engineering one of structural engineering's highest honors. And that would have been the end of the story. Had it not been for a Princeton engineering student who had been encouraged by their thesis advisor to look into LeMessur's innovative structure in this building and to write part of their graduate thesis about this building. The student was Diane Hartley. And in the summer of 1978 Diane placed a fateful call to Bill LeMessur's office in New York. She understood most things about how LeMessur's structure worked. She understood how it reacted to wind and how it was carrying the structural load to those columns at the bottom. But she wasn't quite able to get the numbers to add up on how the building dealt with quartering winds. Now the primary force acting on any building day in and day out is wind particularly perpendicular wind. Other than an earthquake this is the strongest force a building is ever going to encounter. A perpendicular wind hits the building straight on a side and acts like a sail in the wind and it can put extreme force on the building. The building's primary force like I said earlier is its compression strength literally its weight. It's so heavy that the wind can't blow it over or cause it to fall apart. But at the top of the building where there's not as much material stacked on top of each other where the building is not as heavy sometimes the wind can get significant leverage and that's where the the underlying steel structure comes in on the building and supports it in the face of wind that the building is not heavy enough to counter. But that wasn't what Diane Hartley was talking about. She was talking about quartering winds, winds that hit the building from the corner. Now basic understanding of aerodynamics would tell you that this would not exert near as much force on the building because the wind is going to hit the corner the corner is going to split it and the wind's going to flow around right? And in a normal building that would be true but city corp center is not a normal building. So one of Bill LaMeasure's one of Bill LaMeasure's associates answered Diane Hartley's questions and happened to pass along to Bill LaMeasure that he had talked to this student about this. Well LaMeasure also at this time happened to be teaching a class on structural engineering to architecture students at Harvard and he thought that maybe if if this student enjoyed looking into it for a thesis that his class would enjoy a lecture on this building and how the wind bracing in this building worked. So he sat down to do the math and what he realized surprised him. In four of the chevrons a quartering wind resulted in 40 percent higher loads on those angled support structures than a parallel wind or a perpendicular wind. His assumption was that because of where the columns were placed in this building they were actually in the strongest position possible to counter quartering winds but it turned out that that was not true. So 40 percent higher load than they expected on these angled support members. Normally that wouldn't have bothered him because when you build columns in a building there's significant safety margin built in right it's stronger than it has to be to make sure the building doesn't fail. But LaMeasure had been in a meeting in Pittsburgh two weeks prior about a building he was building there that was using the same angular support structure that he had used in City Corp Center and he specced out the same welded joints in those angled support members that he had called Foreign City Corp Center. But US Steel the potential contractor in Pittsburgh came to LaMeasure and said we don't think we need these welded joints here. You see a skilled structural welder can take two pieces of metal and weld them together such that they're just as strong as one piece of metal. But you don't always need it to be that strong and that was US Steel's argument. They said that we can do bolted joints and it'll be plenty strong to support this building. When you weld you have to use a structural welder who is very expensive and it takes them a long time to do this welding. Welding on this scale is not a fast process so it's far cheaper to do bolted connections if you can get away with it. But LaMeasure knew that they'd used welded joints on City Corp Center and he knew that they hadn't had any cost overruns or delays because of it so he called his New York office to get US Steel some reassurance that the welded joints would be fine. And what he learned surprised him. Stanley Goldstein the partner in charge of LaMeasure's New York office told him yeah Bethlehem Steel came to us and said the same thing about City Corp Center. He said there was no reason we needed to weld these joints we can bolt them together and they'll be plenty strong. LaMeasure's New York office had evaluated and approved this change and gotten the new drawings approved by the New York Department of Buildings and it's it wasn't unusual for changes like this to happen in the construction of a big building and LaMeasure didn't think anything of it at the time when he found this out but two weeks later staring at this new information about how his building reacted to quartering winds he wondered if his staff had found the same thing when they specced out the bolts to bolt these joints together instead of welding them. He decided to get on a plane and go to New York so he could see for himself so he got to his New York office he dug out the plans for the building and he found what he said was a subtle conceptual error that made the situation far worse. So what LaMeasure found was that when Bethlehem Steel and his New York staff had considered the diagonal braces and decided how to how to change from welded joints to bolted joints they had considered them trusses not columns. Now this is this little bit of semantics is very significant because according to New York Building Code a structural column has to have a safety margin of two to one. In other words it has to be twice as strong as the load it's ever expected to bear. The requirement for trusses was non-existent there was no required safety margin and so since they had classified these angular support members as trusses not columns who knows how they had built them. So LaMeasure dug further into the plans and he found the detailed bolt diagram on how they had bolted these joints together and he saw far fewer bolts than he would have suspected and he said at this point I was getting pretty shaky but he still didn't have concrete information he didn't he didn't know how bad the situation was he needed exact numbers so he went back to the boundary layer wind tunnel laboratory at the University of Western Ontario. Now boundary layer laboratory is widely regarded to be the worldwide experts on the effects of wind on tall buildings and when they designed city corp center they had done a significant amount of wind tunnel testing at boundary layer you can see the model of city corp center gleaming in the distance in the back of the wind tunnel there. So LaMeasure went back with this new information he had on how sensitive the building was to quartering winds and he asked the staff at boundary layer to check his numbers check his math see if the 40 percent number was correct and so they did and they found that yeah in theory it was correct but in the real world where winds are variable in both direction and intensity the wind could actually get the building oscillating in such a way that the 40 number would go up to somewhere in the 60 to 70 percent range so even worse than he expected he asked the the folks at boundary layer to tease out numbers on every beam and every joint in the building so they teased out load figures for him handed him this pile of raw data and he wanted to go somewhere to think about it to try to figure it out try to figure out what to do about it so he went out to his summer house on a 12-acre private island in mains lake savago and he started pouring through this data that he had joint by joint beam by beam he figured out that the most critical joint in the building was on the 30th floor and once he knew that he set out to figure out what kind of wind it would take to actually cause the building to fail and the thing you need to understand about the word fail in this context is it's a bit of a euphemism normally when you think about a building failing you think about it tumbling straight down and we've all seen videos of buildings being imploded that's not what kind of failure we're talking about here if this joint on the 30th floor of city court center had failed the top of the building would have toppled over into the building next door and could have caused domino effect all the way to central park so that's the worst case scenario that we have in mind here and his bill the measure starts digging into the data what he finds is absolutely terrifying it turns out that a 55 year storm would generate winds strong enough to knock this building over in other words in for each year this building stood there was a one in 55 chance that a storm would come along that was strong enough to make the building fail but then he realized that that wasn't quite the worst case scenario because his math had taken the tuned mass damper into account and if you think about a 55 year storm it's a pretty big storm it's it's going to have strong winds it's going to have a lot of rain a lot of lightning potential flooding and it might knock the power out the problem with a power failure is his tuned mass damper stops working when there's no electricity and as it turns out without the tuned mass damper this one in 55 number is ridiculously optimistic it would take a 70 mile an hour wind blowing for approximately five minutes to cause the building to fail and that's tropical storm strength right new york city sees a tropical storm about every 16 years so le measure realized and by the way it's july when he's working on all of this math so bill the measure realizes that between july and the end of 1978 there is a one in 16 chance that a storm strong enough to blow this building over will come along and so sitting there in his lake house on lake sabego he realizes he has a choice to make if he comes forward with this information he can count on there being a lawsuit he knows he'll get sued he knows the damages will be high enough that it will exceed his insurance policy and likely bankrupt him and he knows that it will ruin his professional reputation he knows those things will happen if he comes forward so he thinks about remaining silent and playing the odds i mean there's a decent chance that a storm this strong won't come along in his lifetime he considers driving into a bridge abutment at 100 miles an hour and taking the news with him to his grave but ultimately he decides he can't do that his morality as professional ethics won't let him do it so he does the only thing he can think of he calls his friend hugh stubbins in the very next morning he and hugh stubbins were sitting in the measures new york headquarters at 515 madison avenue trying to figure out what to do after calling their insurance company conferring with their lawyers they decide that the most immediate thing they need to take care of is getting in touch with city corp and telling them this news about their building so they try to call walter riston and of course fail to penetrate the layers of assistants and secretaries that insulate him from the outside world they try to get in touch with the bank's president second in command william spencer run into the same thing there but they do finally get a hold of this man and get an appointment with him john s read john reads a senior vice president at city corp he's actually the man that succeeded walter riston as the chairman of city corp and he's the third in command not only that he's an engineer by training so when when the measure sits down with him and explains the problems with city corp center and the solution that he has in mind john reads well prepared to understand it and this is where hugh stubbins saved bill the measures bacon because the solution to this problem is actually pretty easy since stubbins insisted on having his sleek aluminum and glass exterior all of the structural supports in the building look just like this so in order to fix the building all they have to do is go bust the straw wall open and weld on two inch thick steel reinforcement plates over all these vulnerable joints not really that big a deal they could do the work at night when the building is vacant so they could turn the firearms off the firearms wouldn't go off because of all the the thick smoke that would come from welding these joints they could build little plywood shacks around the joints to keep tenants property safe and they could box they could accomplish these welds in a single night so they could get the repair done repeat repair the drywall and be out before the tenants came to work the next morning john read was pretty satisfied with this answer the only question he had for the measure is how much it was going to cost and the measure gave him an off-the-cuff estimate of me about a million bucks and so john reads sent them back to their office and told them to await further instructions less than an hour later john read walked into bill measures office with none other than walter riston himself now you can tell by looking at walter riston that he's not exactly a kind and gentle man but on this day his focus was on saving his building he was genuinely proud of it he wanted it to stand the test of time and so they started discussing what they were going to do to save this building and somewhere along the process walter riston knowing he's eventually going to have to draft a press release about this repair work that they're about to undertake asked for something to write on and somebody hands him a yellow legal pad well walter riston laughs at that looks around the table and says gentlemen every war has been won by generals writing on yellow legal pads but more important than what he said is what he did he laughed he defused the tension in the room he let the team start focusing on solving the problem instead of worrying how he was going to react his laughter put everyone at ease and they got to work putting together their plan hours after this meeting they had not one but two backup generators on site to make sure that the tuned mass damper stayed powered if the power went out the next day they met with engineers from carl cope construction on an unoccupied floor of city corp center carl cope was the firm who would be doing the repairs and so on this unoccupied floor they they knocked down they knocked out the drywall in one of these angular wind braces so they could see what was actually in there and if it was going to be feasible to do the repair there were just as few bolts as bill the measure was afraid there would be the situation was just as dire as he had said it was the good news was the engineers from carl cope said yeah this is this solution is definitely feasible we can absolutely fix this not only that but they also had enough steel two inch thick steel plate on hand to do the repairs so city corp drew up a contract and as soon as the measure got new drawings made and got them approved by the city of new york work would begin on the repairs the circle stayed pretty tight through the first week of august but like i mentioned they had to get approval for the repairs they were going to do they had to get them approved by the new york department of buildings so bill the measure found himself on the morning of august the eighth sitting with the new york city commissioner of buildings and nine other senior officials from the city of new york spilling his guts this is the meeting he'd been afraid of this is the meeting he expected to walk out of having lost his professional license to practice engineering so he told him everything that had happened how it had come to pass and the city officials asked a few technical questions and they guaranteed their support and expediting the repairs as much as they could and then they did something bill the measure wasn't expecting they commended him for his courage and candor and coming forward with this information the exact opposite of the censure he was expecting to receive and the department of building support came in a couple of key ways the first neil morten one of the city's most respected steel inspectors would remain on site every night they were doing the work so when they completed one of these welds morten could come in and look at it approve it and they could get the drywall back up before the tenants were in the next morning but more importantly there was a a significant shortage of structural steel welders in new york at that time and they gave morten unprecedented authority to conduct and certify welders on structural welding on the spot so there were steamfitter welders all over the place that could do a fantastic job doing the structural welding they just hadn't passed the city's welding test and they gave morten the authority to do that on the spot second they worked with the mayor's office of emergency management the new york police department and the new york red cross to create an evacuation plan they decided the building was safe in all but the most extreme wind circumstances but they still wanted to be prepared in case a storm came along so new the the new york red cross sent volunteers out into the surrounding neighborhood to canvas the neighborhood figure out how many people were there during the day and how many people were there at night and where they were so they would know who they were going to have to evacuate and how many people they were going to have to provide for in the event of an evacuation the building lit up every night with the work of the welders in a race against the unknown they had no way of knowing if and when a storm might come along that would be strong enough to blow this building over so they were working on the repairs as quickly as possible and they were really lucky until around the first of september hurricane ella was churning off of the shore and had turned towards new york so the measure convened an emergency meeting with city court officials about 6 30 in the morning on the morning of september the first and so the good news is we've got the building strong enough that it can withstand a 200 year storm so a storm that would come along every one in 200 years the bad news is hurricane ella might be a 200 year storm there's no way for us to know how strong it's going to be when it hits shore so we need to start thinking about our evacuation plan they watched the storm the remainder of the day and they were about an hour away from enacting the evacuation plan when ella decided to turn back out to sea they all breathed a big sigh of relief by september the 13th the crisis was largely over the building was strong enough that it would withstand a 500 year storm at that point it might be the strongest skyscraper in existence due to this repair work but as the crisis wound down it started to look like the lawsuit that bill le measure had dreaded so long was finally going to come to fruition city court served him with notice that they intended to seek recovery of all costs involved in repairing this building from him and his firm but an interesting thing happened city bank actually never filed suit on bill le measure they sat down at a conference table much like this one bill measure on one side two senior vice presidents from city corp on the other no lawyers and the measure offered a two million dollar settlement the city court vp's pressed back said they'd been seriously wounded but they did it without a lot of conviction their heart wasn't in punishing bill a measure for what had happened the next meeting the only lawyer present was the one from bill the measures insurance company and the only reason that lawyer was there was to work out the details of transferring the two million bucks to city corp they agreed to hold huge stubborn firm harmless and they agreed to settle with bill the measure and his associates for the two million dollars that his insurance company was willing to pay various estimates put the cost of repairs somewhere in the four to eight million dollar range depending on how you value the time of the city corp execs that were involved and what about diane hartley the engineering student that brought this to bill the measures attention in the first place she had no idea any of this even happened so there's several interviews with bill the measure where he talks about city corp center and he talks about how he came to know there was a problem with this building and invariably in these interviews he refers to quote a nice young fellow from princeton unquote now most most people say that the measure never actually talked to this student himself he never talked to diane hartley he was an associate to talk to her 20 years after all this took place diane was at home and her husband yelled out to her honey the building you did your graduate thesis on is on tv come watch and so she came in there and she heard bill measure say this she heard bill measure talk about this nice young fellow from princeton and she wondered who could this be who is who is this person that realized the same thing that i did and so she calls her thesis advisor and she asks her thesis advisor about this and he says diane nobody else studied this building the nice young fellow has to be you diane hartley actually never had the chance to beat to meet bill the measure he died before she ever found out that this chain of events occurred in fact nobody knew this chain of events occurred until there was an article in the new yorker 20 years later it's one of new york's best kept secrets and it's one of my favorite stories to tell i've read it several times over the years it's a great story to be sure this building that nearly fell down but my favorite thing about it is probably what it's lacking there's no animosity anywhere in this story the end of the day the building got fixed nobody sued anybody and everybody was made hold of their satisfaction over a couple of conversations so in our hyperlitigious society how does something like that happen well there's things that bill the measure did and things that city court did that brought them to this kind of conclusion bill measure was transparent as soon as he realized he made a mistake and he grasped the scope of it he fasted up he came forward remember all those things he was afraid of a lawsuit bankruptcy losing his professional reputation knows happened in fact the opposite happened this story is used in engineering classes all over the country as an example of professional ethics in engineering his story is held up as a case study of the right thing to do in this scenario his reputation was enhanced now when you make a mistake like this the temptation is always to think about all these things that are going to happen to you your brain hopefully builds up the worst case scenario so that when the consequences of your actions eventually do come home to roost you'll be prepared for them because you've already prepared for something far worse than is actually going to happen the side effect of your brain doing this is that you're far less likely to come forward and to admit when you've made a mistake like this and that's almost always the wrong decision it's almost always the wrong decision when you make a mistake to try to fix it yourself try to hide it from your co-workers because if you get together with your co-workers and you talk about what's happened you'll come up with a better solution to the problem and you'll come up with ways to not repeat problems like this so as engineers we have to learn to push back that instinct to hide when we make a mistake to think about the worst case scenario it's not helpful it's not a helpful instinct bill and measure also was solution-oriented when you have one of these conversations when you've made a mistake and you have to go to your boss about that mistake bring a solution with you and that does something very important it focuses your conversation not on blame for what happened but on the future on the solution on moving forward it lets the people you're talking to know that you're all in the same team this was an honest mistake you certainly didn't intend to do it and it helps you move the conversation forward it helps the conversation not devolve into the blame game so if you make a mistake as an engineer you should be transparent and you should be solution-oriented but what if you're on the receiving end of this mistake i'm sure there's some of you in this room that are team leads or managers and are sometimes on the receiving end of conversations like this there's things that city corp did that we can learn from as well first of those is blameless keep the conversation blameless Walter Riston did not build the measures head off when he brought this attention this this problem to his attention he easily could have he was one of the most powerful men in banking he could have brought financial ruin down on bill the measure and all of his associates if you had wanted to do so but he didn't he came to the table he kept the conversation blameless and he focused on fixing the problem now if you can do that with the people that work on your team you can delay the conversation about what happened and how to prevent it from happening to the future once your emotions and their emotions have faded you can have a calm rational conversation once your brain is not in that emotional space where you're trying to deal with that mistake in the moment where you're not in that panic emergency mode of trying to keep production up the other thing that walter riston did that was so important is he was kind remember what i said earlier about how we build up worst-case scenarios on our head when when someone on your team comes to you with a mistake that they've made they're they're probably expecting a few things to happen they're expecting you to yell at them they're expecting to be embarrassed in front of their teammates they might even be expecting to be fired so you piling on in that moment when they are in this raw emotional state bringing a problem to you is not helpful it's one of the least kind things you can do this is an opportunity as a manager for you to build trust if you're calm and measured in your reaction if you keep the conversation kind and focused on the solution you're showing your employees that they can trust you they can bring mistakes to you and you're not going to knock their head off you've got their back and you're showing that you trust people on your team to be grown-ups and learn from their mistakes you're showing that you trust their intentions that you know they didn't make this mistake on purpose you know that they acted with the best of intentions with the best information they had at the time and when you show that to your teammates they start coming to you with problems like this they start coming to you and asking you for help and that ultimately is what you're there for as a team lead or as a manager as a VP of engineering as a CTO you want your people coming to you to consult with you when they face a problem but the overarching truth in the story to me is that mistakes are inevitable we move fast in our industry we're always adopting new tools and new processes we're building things in new and novel ways bill the measure did this before bill the measure built this building with this super light steel skeleton engineers everywhere relied entirely on compression strength to hold their buildings up nobody had tried to build a building like this where it relied primarily on the steel structure underneath not the structural compression strength to hold it up in the wind in doing that he made a significant mistake but he also introduced technology into structural engineering that allowed us to do things like build Taipei 101 Taipei 101 in the Burj Khalifa without lightweight steel skeletons buildings that tall wouldn't be possible because they would be too heavy for the earth to even support they would sink as soon as you got them built but because of these lightweight steel skeletons that build a measure pioneered we can build buildings like that if he hadn't been willing to push the state of the art we wouldn't be able to build super tall buildings but because he knew how to cope with his mistake because he had trust in his colleagues and he could go to them and he knew that they could solve this problem and keep this building standing he was able to push the state of the art of structural engineering forward so if you as a software engineer or as a team lead or as a cto want to push the state of the art of software engineering forward you also have to be willing to make mistakes in the process because you will it's inevitable but if you spend time investing in how to respond to these mistakes how to treat your team well when they come to you with one of these mistakes you will have invested in the future of your business and in your business's ability to innovate thank you