 So before I get rolling, what a great conference today, am I right? Did everybody enjoy it? So I want to give a shout out to the four amazing organizers that make it possible for us to all be here today and hang out together, Terrence, and Britt, and Caleb, and Richard. Thank you all so much for all the work that went into this, I know it wasn't easy. And how about Brandon Hayes? I have never seen an MC go to so much effort to make sure that everybody had their own piece of crappy sonic fan art. And I'm especially pleased at the facial hair synergy between myself and Dr. Robotnik that did not go unnoticed. So if you've seen me speak before, you have a pretty good idea of what I'm about to do. My shtick is I get on stage and I tell stories. And I've got a brand new story for y'all today that I'm pretty excited to get to tell because it's one of my favorite stories. It's not about airplanes. There are no airplanes at all in this talk, as a matter of fact. It's about the building built on stilts. And our story today takes place in New York in the 1970s. Now, if you know anything about America in the 1970s, you know we were going through a major economic depression. We just got out of Vietnam. There was an oil embargo that caused runaway inflation. There were abandoned construction sites everywhere in New York. All these projects had been started and run out of money and hadn't been completed. This picture of the New York subway is a pretty good portrait of the state of public infrastructure in the state of New York in 1970. They didn't have any money to take care of anything. They couldn't even clean up the graffiti on the subway cars. The city of New York itself was perilously close to bankruptcy. And they might have gone bankrupt if it weren't for the efforts of this man, Walter Riston. So Walter was a businessman who happened to be very civically minded and he didn't want to see his city of New York go bankrupt. So Walter worked with the New York legislature to set up this concept called municipal assistance corporations. Where a city could set up a corporation and sell bonds and use those bonds to finance the ongoing operations of the city during a time of financial hardship. So once that was through the legislature, Walter went all over the city of New York persuading the big union pension funds and the big banks to fund these bonds, to buy them, to invest in their city. What helped that Walter was better known as the chairman and CEO of one of these very banks that was buying bonds. The first national city bank of New York. This is a bank you've all heard of, you just don't know it. This is city bank. Now in the mid 70s, city bank was actually sitting in pretty good shape despite the recession. They diversified their investments. They had spread out their loan portfolio. They were financially solid. The biggest problem that city bank faced in the 1970s is that they were out of room at their headquarters. There was no office space left at 399 Park Avenue. Now they could have gone to an adjacent building and rented out a couple of floors. That's what a sane person would have done. But Walter Riston was not a sane person. He was a businessman and he had businessman sized objectives. And so instead of just leasing space in an adjacent building, he decided he wanted his own building. And he wanted it to be a signature building. There were two things that he wanted to say with his building that he wanted to build. He wanted to show that number one, despite the recession, city bank was still in great shape. They were still a very stable bank. And number two, he wanted to show that they were still committed to New York. They weren't going to go anywhere. Despite these crumbling construction projects all around, despite the decrepit state of the subway, they were committed to New York for the long haul. And the way that Walter Riston saw best to do that was to build the signature building. So they started buying up property. Their current headquarters were at 399 Park and they started buying the city block right across the street from 399 Park. There was a problem, St. Peter's Evangelical Lutheran Church. The good people of St. Peter's liked their church building right where they had it. And where they had it was right on the prime corner of Citibank's lot, right at 45th and Lexington. They were the last holdout on this block. Citibank literally owned the rest of this block and they needed the full block for the foundation of this building. They had aspirations to build a tall tower that would stand out on the skyline and you need a lot of foundation to do that. So they started negotiating with the church. Well, the church's congregation had been hit by the recession just like everybody else. The church was in bad shape and their giving was down so they didn't have enough money to refurbish their building. So he said, sure, we'll sell you our property, but you gotta build us a new church. And Citibank said, well, sure, we can do that. Where do you want it? St. Peter said, right where it is. Not only did they want it right where it was, they didn't want any support structure for the skyscraper to go through it. They didn't want there to be any adjoining walls. And they were unwilling to negotiate on that point, or at least Citibank wasn't willing to pay enough money for them to negotiate on that point. So what else was Citibank gonna do? There were no other terms being offered. They had to say yes to this proposal, it was their only option. So they agreed. And they bought the air rights above St. Peter's Church. This is actually the first air rights transaction in New York real estate history. Well, Riston presented this conundrum to his architect for the project, a man named Hugh Stubbins. Riston needed a building, a plan for a building that would allow this church to be on the corner it was already on. And so Stubbins had this idea, well, what if we can't deliver one corner of this giant building over the church? We just let it hang over the top, seems to make sense. So Stubbins brought in his structural engineer for the project, a guy named Bill LeMesure. He said, Bill, how about we cantilever one corner of this building over this church? Can we do that? He said, sure, that shouldn't be a problem. So then Stubbins got to thinking about it, and he said, well, what if we cantilever two corners for symmetry? I think it would look nice. LeMesure thought about it a little bit, and he said, well, it'll be a little harder, but I'm sure I can come up with a structure that'll do that. Then Stubbins got greedy. He said, Bill, we could create a really dramatic base for this building. And provide a lot of public space if we cantilever all four corners. And so, believe it or not, that's what they did. So there's St. Peter's Church right there at the corner of 45th and Lex. You can see the building hanging over it. I don't know about y'all, but it doesn't seem like those skinny little columns should be enough to support that giant building. That's actually the genius of Bill LeMesure's design, figuring out how to do this. That's not a manipulated photo. That's actually the base of that building. That's what it looks like. One of the most really great ideas this one came about in an Abton sketch. Bill LeMesure was sitting at his favorite Greek restaurant close to his office in New York when he came up with this idea for these diagonal wind braces. Let me explain a little bit about how this works. So in most buildings, the bulk of the structural load is carried by columns that run down the corners of the building. It goes from the top straight down to the bottom. But what happens when those corners don't go all the way to the bottom? Where does that weight go? That was the problem Bill LeMesure had to figure out. So you can see the basic idea in his napkin sketch. There's a series of inverted chevron braces that direct the load of this building to these center columns. A series of six of them, eight stories tall apiece. And so if we take one floor in the middle of the building, we can see how this works. The weight of this floor goes down the center and the exterior walls of the building down to the chevron below it. And the chevron concentrates the load over that central column. So the chevron takes care of handling structural load. Not only that, it handles wind load. So when wind is blowing on one side of the building, the chevron takes that load from the face of the building and transfers it to the central column. So LeMesure was satisfied that his design was safe and was going to hold the building up and he presented his plans to the New York Building Authority. They agreed with him. They approved the plans and construction began. Now LeMesure, self-confessively, has a big ego. And he tried really hard to convince Hugh Stubbins to put his diagonal supports on the external face of the building so that everybody could see them. But Stubbins was insistent that his glass and aluminum facade be the only thing that you can see. So this is the last time you can actually see these braces intact at their full height when the building's under construction. Now the interesting thing about this picture, I don't know about y'all, but that doesn't look like very much steel to me. And actually it's not. So the steel skeleton of this building weighs about 25,000 tons. Compare that to the Empire State Building, a similarly sized building, a little bit taller. The steel skeleton of the Empire State Building weighs 60,000 tons. So this building is feather white, feather light by comparison. Now this lightweight enabled the building to stand up on stilts, but it caused a problem. The building was much less resistant to the wind. Now something you may not know is that all tall buildings sway to some degree. You can actually build a much stronger building if you give it some give, if you let it move around a little bit, then if you build it completely rigid. And buildings could actually sway quite a lot and still be structurally stable if it weren't for their feeble occupants. Because if you and I were sitting on the 59th story of the city, city court center in the middle of a windstorm and the building started swaying around, we would both be nervous that the building was about to fall over and probably significantly seasick. So LeMesure knew that and he installed the first tuned mass damper in a skyscraper in North America. Now what this thing is, is a 410 ton block of concrete, that big yellow thing at the top, is a 410 ton block of concrete. And it floats on a thin film of oil to counteract the movements of the building. And it's easiest to explain how this works by showing it. So I actually found a video of the tuned mass damper in action. Now the thing to note about this video is that block of concrete is actually the stable thing in this video. The building is moving around it. And so what happens is, is the building moves out from under this giant block of concrete, it very slightly shifts the center of balance of the building and that serves to suppress the sway of the building. So this is the first one of these installed in a building in North America. They're actually pretty common now. When city court center was completed, it was actually the 7th tallest building in the world at the time back in 1977. It was 914 feet tall and 59 stories. It was received with positive reviews by and large. Stubbins got a lot of credit. The New York Times said that Stubbins had indeed created one of New York's significant buildings. But Stubbins wasn't the only one that got credit. Bill LeMesure got a lot of credit for this building as well, for the innovative structural skeleton. So LeMesure was actually elected to the National Academy of Engineering, one of the field's highest honors. And that would have been the end of the story. Were it not for a Princeton engineering student who'd been encouraged by their thesis advisor to look into this building? That student was Diane Hartley. And in the summer of 1978, about a year after this building had been completed, she made a fateful phone call to Bill LeMesure's office. In investigating this building for her thesis, she understood most things about how a structural design worked. She understood how it was bearing load in most situations. But she couldn't quite put together how it was handling quartering winds. Now, the primary force acting on a building day in and day out is wind. Unless it's in an earthquake zone, a perpendicular wind is the strongest force a building is likely to ever see. The building acts much like a sail standing into the wind. The building's primary defense against the force of the wind is its compression, compression string, literally the weight of the building. It holds itself together just because it's heavy. Now, at the top of the building, the wind can develop enough leverage that that's not enough. And when that happens, the structural skeleton of the building is the thing that has to make up the difference. So between the compression force and the tension in the building's frame, the building can stand up to wind. But Hartley wasn't asking about perpendicular wind. She was asking about quartering wind. Now, New York City building codes in 1977 didn't even address quartering winds. And there was a good reason because buildings were strongest at their corners. There was no need to calculate quartering winds because if you calculated for perpendicular winds and your building could stand up to perpendicular wind, there was no reason to worry about the quartering winds. And you can tell from basic aerodynamics that the wind should essentially just flow around the building when it hits it in the corner. It should exert much less force. But this was not an ordinary building. One of Bill LaMeasure's associates answered Diane Hartley's questions to her satisfaction. But then they mentioned this to Bill LaMeasure in passing. And it was a little disconcerting to LaMeasure. He realized that he had done all the math for perpendicular wind. He had thought hard about that because the building code required him to, but he hadn't really considered quartering winds and that got him curious. He wondered how his building stood up to quartering winds. So he sat down, needed to quit pass at the math just to see. And to a surprise, he found out that these angular wind braces experienced 40% higher load than he expected under quartering winds. Load beyond what they faced in perpendicular winds. And normally that wouldn't have worried LaMeasure because when you build a big building like this, there is a safety margin that's required in the structural skeleton, right? You have to build it stronger than it actually has to be. In part because sometimes you do screw up a calculation like this and you want the building to be able to bear it if that happens. And sometimes because it undergoes forces that you don't expect it to undergo. But LaMeasure had learned something the week prior that gave him pause when he learned this 40% number. He'd been in a meeting in Pittsburgh about another building that he was the structural engineer on and he was using the same angular bracing structure that he'd used in City Corp Center and he'd specced out the same welded joints that he'd specced out for City Corp. But US Steel, the potential contractor for this building at Pittsburgh, had pushed back. He said, we don't need welded joints, that's too strong. So the thing about welded joints is a skilled welder can actually make two pieces of steel just as strong as one by welding them together. And sometimes you don't need all that strength. Sometimes a bolted joint is just fine. And that's what US Steel had argued that there was no reason to go to the expense and time of welding these joints because skilled structural welders are far more expensive than structural constructors who can bolt things together. But LaMeasure really wanted his welded joints. So he called his office in New York to give US Steel some reassurance that these welded joints wouldn't be any problem, wouldn't be any big deal. And what he learned surprised him. Stanley Goldstein, the partner in charge of LaMeasure's New York office told him that Bethlehem Steel had essentially made the same argument about City Corp Center, that the weld joints were overkill, that there was really no reason to weld these joints together, that they get the building built faster and cheaper by just bolting them. And the New York office had approved it. They had submitted new offices to the New York buildings department, and that's the way the building was put together. The joints were bolted. But the thing that LaMeasure found himself wondering about, now that he knew that certain structural members in this building underwent 40% higher force than he expected them to, was if his staff in New York had found the same thing when they specked out the bolts for putting this building together. He wondered if they knew about the 40% increase in load. So the next morning, he got a shuttle flight from Boston to New York to have a look at the plans himself. And digging into them, he found what he calls a subtle conceptual error. And that made the problem far worse. What LaMeasure found, much to his alarm, was that Bethlehem Steel in his office in New York had classified these diagonal braces not as structural columns, but as trusses. And that distinction is important because a truss doesn't have the same safety margin requirements that a structural column does. You don't have to build a truss double string like you do a column. And so LaMeasure said, when he pulled open the drawings and he looked at the bolt patterns they had specified for bolting these giant angular wind braces together, he found far fewer bolts than he would have expected. And he says, by then, I was getting pretty shaky. But before LaMeasure could really figure out the full situation and the extent of the problem, he needed exact numbers. He needed to know exactly what the situation in this building was. So we went back to the boundary layer wind tunnel laboratory at the University of Western Ontario. Now the boundary layer wind tunnel laboratory is the world's foremost expert on how tall buildings behave in high winds. When they designed this building they had actually done wind tunnel testing at boundary layer. They built them all. You can see the obvious angled roof line back in the back there. They had done wind tunnel testing to see how this building would stand up in the wind but that was before they had realized that those angular structural members underwent 40% higher force than expected. So we went back to boundary layer. He had them pull out all of the test results and he had them rerun the calculations based on the new strength data. He wanted to know if this 40% calculation was correct and what the implications for the stability of the building were. Well it turns out his 40% number wasn't right. It was optimistic. In variable wind conditions where the wind was pulsing it could actually get the building oscillating and exert significantly higher than 40% more force on these angled supports. And so LeMessure said, LeMessure asked for load data for every structural member in every joint in this building. And so boundary layer ran that through their computer systems and handed him all this data. By this point, Bill LeMessure was pretty distraught. He knew he had a big problem on his hands and he was trying to figure out what in the world he was gonna do about it. And so he went out to his summer retreat to clear his mind. On a 12 acre private island in the middle of Lake Sebago in Maine, he poured over this data joint by joint, beam by beam, trying to make sense of it, trying to understand what flaws lured underneath the skeleton of his beautiful building. He learned that the most critical joint was on the 30th floor and that failure there would cause catastrophic collapse of the rest of the building. Now we're not talking about the kind of catastrophic collapse where the building just falls straight down like you see when they implode something with dynamite. We're talking about the top half of this building tipping over and potentially creating a domino effect that some experts said could have gone from city corp center all the way to Central Park knocking over eight to 10 buildings in the process. So once he had that happy piece of data, he set out to figure out what kind of wind it would actually take to cause this joint on the 30th floor to fail. And what he found was terrifying. What he found was that a 55 year storm would be strong enough to cause this joint to fail. What that means is in any given year, there is a one in 55 chance in New York City of a storm strong enough coming along that could cause this building to fail, one in 55. I'd take those odds in Vegas. But of course that wasn't quite the worst case scenario because in a major storm, it's pretty likely that you're gonna lose electricity. And Bill LaMeasure's fancy tuned mass damper up on the top of city corp center relied on electricity to do its job. Bill LaMeasure realized that he had included the tuned mass damper in his calculations when he was trying to figure out the worst case scenario for this building. So that one in 55 number, turns out that was wildly optimistic. All it would take is a 70 mile per hour quartering wind sustained for around five minutes. So essentially a tropical storm. And a tropical storm hits New York City about once every 16 years. So this is all taking place in July, the very beginning of hurricane season. And so as Bill LaMeasure is sitting there in his lake house in Maine, he realizes that between then and the end of the year, there is a one in 16 chance that a storm that's strong enough to knock this building over will hit New York City. And so he had a decision to make. He knew that if he brought this to city corp's attention, that it would bring almost certain litigation, that it would possibly bankrupt him and that it would unquestionably flush his reputation as a professional engineer right down the toilet. He would never work again. He knew this. So he contemplated remaining silent. He contemplated driving into a bridge about a minute, a hundred miles an hour. But he couldn't bring himself to do those things. His morality and his sense of professional ethics as an engineer just wouldn't let him do it, thankfully. So he picked up the phone and he called Hugh Stubbins. And the next morning, he and Hugh Stubbins met at La Measures firm at 515 Madison Avenue in New York City to try to figure out what to do about this. The first thing they tried to do was get ahold of Walter Riston. But of course, it's really tough to get ahold of the chairman of a Fortune 500 company. They didn't have any luck getting through the layers of secretaries and assistants that protected him from the outside world. Nor did they have any luck getting in touch with the bank's second in command, President William Spencer. But they did get an appointment with this man. John S. Reid. Now, Reid was a city group senior vice president who would actually succeed Riston as the chairman. Reid had a background in engineering, so he had no problem following the problem that La Measures was bringing to his attention or the solution that La Measures was describing. This is where Stubbins insistence on his clean aluminum and glass facade saved Bill La Measures Bacon. Because the solution to this problem was actually pretty simple. All of these crucial joints were exposed on the inside of the building. They could get to him. All they had to do was go to the joints and knock the drywall off and weld a two-inch thick steel mending plate over each vulnerable joint. They'd do the work at night when the building was vacant so they wouldn't disturb the tenants. They could build a little plywood shack around each joint that they needed to weld so that they could protect the tenant's possessions. They could even turn the building's fire alarm system off at night so that all the smoke that they produced by welding wouldn't set off the fire alarm system. The only real question Reid had about this plan was how much it was gonna cost. And Bill La Measures shot him an off-the-cuff estimate of around a million bucks. And so, John Reid sent La Measures and Stubbins back to their office to await further instructions. About an hour later, this scowling face walked into their office with John Reid, Walter Riston himself. Now, Riston, as you can tell by this photo, is not known for being a particularly happy, friendly man. He's intense. He's dour. He has the fortitude of an individual who would run a company like Citibank back in the 1970s. He fit the executive profile of that day. But his focus that day was on saving his building. He asked for something to write on to take notes for the press release that he knew he was eventually gonna have to write and somebody handed him a yellow legal pad. And that made him laugh. He looked around the table and he said, gentlemen, every war has been won by a general writing on a yellow pad. And Riston's humor did something in that room that was very important. It put everyone there at ease and let them focus on the problem at hand and solving it. They got to work putting together their plan. Within hours of the meeting, they had arranged for delivery of not one but two backup generators to make sure that the tune mass damper stayed powered so that they could at least keep their baseline failure rate to one in 55 years rather than one in 16. The next morning, Bill LaMeasure and several other associates showed up on an unoccupied floor of City Corp. Center to meet with engineers from Carl Koch Construction, the firm that would be doing the repairs. And the first thing they did was knock open one of those joints to see if this repair was even gonna be feasible. Sure enough, they knocked it open. The bolts were as scarce as LaMeasure was afraid they would be, but the repair was feasible. The engineers from Carl Koch said, no problem, we can absolutely do this repair. And better than that, we've got all the two inch steel plating on hand that we need to do it. We'll get started cutting it right away and we can start welding on the building as soon as you have new drawings approved. They went to the National Weather Service Office, which in 1970 was actually located at 30 Rock. You can see the ray dome on top of the building there. They spoke to the meteorologist in charge to brief him on the situation at City Corp Center and to ask for meteorological support so that they would know if there was a major storm coming that was likely to knock over their building. They wanted as much notice of potential wind events as they could get. The reason they needed that was because of this man, Leslie Robertson. Now, City had brought Leslie in as a consultant on this project. He is one of few peers that Bill LaMeasure has in the world. He's a structural engineer that does the same caliber of work as Bill LaMeasure. Leslie Robertson's claim to fame is he did the structural design of the Twin Towers of the World Trade Center. And Robertson's first action after verifying LaMeasure's plans and agreeing that they were appropriate and would solve the problem was to insist that they create an evacuation plan so that if the weather turned and there was even a remote chance that a storm might knock this building over that they could get everybody out of harm's way. But they had to do it quietly. They didn't want to cause a panic. They didn't want to cause a large area of Manhattan to be permanently abandoned while they fixed this building because there was no reason for that level of alarm. There was no imminent danger. So they brought in the New York Red Cross to go door to door, survey all the businesses and all the residences and figure out how many people they were talking about having to move during the day and at night in case they decided they needed to enact this evacuation plan. Meanwhile, the work began in earnest. The city of New York had assigned a building inspector to be on site all night long while this work went so that when they finished one of these joints the inspector could come and inspect it and they could immediately box it back up so that they could fix one of these joints and have the drywall repaired and the office cleaned up overnight before the tenant got back in the next day. They also gave this building inspector extraordinary power to approve new structural welders on site because as you can imagine there's not a lot of skilled certified structural welders that can do this caliber of work but New York does have a lot of steam fitter welders because there's a lot of steam heat in New York. And steam fitter welders can weld structural building structural welds just fine. They just needed to be certified. The building lit up every night with the work of the welders and a race against the unknown. They had no way of knowing what their actual deadline was because there was no way to know if a storm was gonna hit New York that year. And their luck held out until the very end of August. About 6.30 in the morning on September 1st Bill LaMesure got a call from the National Weather Service. Hurricane Ella was headed towards Cape Hatteras and it turned up the coast and it was headed towards New York. Now the problem they faced was that the evacuation plan that they had designed needed plenty of advanced notice for them to be able to actually get everybody out of harm's way in time. And so they had to make a call on this long before they knew for sure if the storm was gonna hit New York. Long before they knew if even if it did hit New York if it was gonna be strong enough to knock over the building. So they had an emergency meeting. LaMesure and Leslie Robertson and City Corp execs got together and talked about this to try to figure out what they were gonna do. The building was now strong enough that it would withstand a 200 year storm. So this would have to be a pretty significant hurricane to cause the building to fail at this point. But nobody knew what strength Ella would be on landfall. Nobody knew how strong it would be. They were actually that afternoon about an hour away from making the call to an active evacuation plan when Ella decided to turn back out to sea. By September the 13th, the building was strong enough that they no longer felt the need to keep up the weather watch. They no longer felt the need to maintain an evacuation plan. Everybody calmed back down. The crisis was essentially over. They had saved the building and with the building saved, all the things that LaMesure was afraid of began to pass. City Corp had been focused on getting the building fixed all summer. But now that the crisis was over, they served LaMesure with notice of their intention to seek repayment of all costs involved in repaying this building. But something interesting happened. City might never actually filed suit against LaMesure. Two senior vice presidents from City Corp sat down on one side of the table. Bill LaMesure sat down on the other. He offered them a $2 million settlement. Now City pushed back, but in the words of Bill LaMesure, they didn't have a lot of conviction in their pushback. At the second session between them, LaMesure's insurance lawyer was the only lawyer present. He was only there to drop a settlement. City Corp agreed to hold Houston's firm harmless and to accept the $2 million settlement from LaMesure's firm. Now various estimates put the cost of these repairs somewhere in the $4 to $8 million range. So $2 million didn't come close to covering their expenses. But they agreed that $2 million would make them whole. And that's the remarkable thing about this whole story. We're talking about a giant investment on the part of City Corp. A huge bill to fix it when something went wrong. At the end of the day, the building got fixed. Nobody sued anybody and everyone was made whole through a couple of conversations. Let's talk about why that happened. So the first important factor is that Bill LaMesure was remarkably transparent. As soon as he realized the significance of this mistake, as soon as he had a handle on the scope of it, he fast up. He called City Corp into the room and told him exactly what had happened. Remember all those things he was afraid of? A lawsuit, bankruptcy, lots of his professional reputation. None of that happened. He never got sued. He certainly didn't go bankrupt. He actually didn't pay anything. His insurance company paid the entire $2 million of the settlement. And his professional reputation that he was so afraid he would lose if he confessed this. The opposite actually happened. The story of City Corp Center is actually used in engineering classes all over the country as an example of professional ethics in engineering. Bill LaMesure is held up as an example of fantastic ethics in his field. And when you make a mistake, when you ship code, when you bring production down in the middle of the night or delete a crucial table out of your production database, your mind immediately goes to worst case scenarios. You know that your boss is gonna part your hair with his anger. You know that your coworkers are gonna think you're an idiot and never trust you with anything again. And you know you're gonna lose your job. But those things rarely happen. You see, our brain plays a funny trick on us. Our brains are really good at preparing us for worst case scenarios. So that what actually happened doesn't seem like that big a deal. It's a subtle psychological trick that our brains play on us. The side effect of it is, is if you listen, it can make it really tempting to try to fix the mistake yourself for to cover it up to not share it with anybody, not share it with your team who can help you make it right. And that's not what you want to happen. Because when you make a mistake like this, you're not in any position to be trying to fix it yourself. Another thing that Bill Immeasure did that was remarkable is he was solutions oriented in this building. He didn't just come to John Reed and go, well, I screwed up your building. So when you go to your boss to tell them that you dropped a table out of the production database, you should probably be prepared with the time stuff of the latest backup that you have of that table. And you should have an idea of what it's gonna take to repair that table. Because if you walk into that meeting with a solution, you change the tone of that meeting significantly. You shift it away from being backwards focused. You shift it away from being focused on finding blame. And you make it a forward thinking. You make it forward thinking to finding a solution and moving forward. You show this person that you're confessing your mistake to that you're on the same team. That you just screwed up but you certainly didn't mean to. It helps the conversation not devolve into the blame game. It helps you move forward and solve the problem. So if you make a mistake, you should be transparent and solution oriented. But what about if you're a manager? What about if you're on the other side of the table and somebody on your team is coming to you with this kind of information? Well, there's some significant lessons to be learned in how Citibank conducted themselves in this story as well. The first thing, Citicorp kept the conversation blameless. And you saw that look on Walter Riston's face. I bet he could choose somebody up one side and down the other if he wanted to. And I bet he's done that a number of times in his career. But he didn't do that here. There's always plenty of time to figure out why something happened and how to keep it from happening later. It's always a systemic problem. People on your team aren't setting up to be malicious and screw things up on purpose. So it's up to you as a manager to create a system around your team to help them be safe when they're doing their work, to help them not be able to break things like that. And when they do, and as they inevitably will and they bring it to you, you owe it to your team members to keep a level head. Because remember that subtle trick that your brains play about preparing for the worst case scenario? Well remember, this person that's talking to you is doing that very thing. They are expecting you to yell at them. They are expecting you to fire them. So unless you're gonna do that, that's not what they need from you. They need you to not pile on. They need you to be supportive and calm and measured and help them implement the solution that they're bringing to you. There's always time to talk about this later and you owe it to them to follow up on it later to find out what they learned from the situation. But nobody's gonna learn anything if you try to figure that out in the heat of the moment. Wait until you're calm and rational and can have that conversation. The other thing City Corp did is they were kind. Walter Riston didn't chew Bill LeMesure out. Instead he built trust. He built upon the trust that he already had in Bill LeMesure. And they remained partners in this project through the end. They got the building fixed and it still stands on the corner of 54th and Lexington and New York to this day. But the most important thing that you need to remember is that mistakes are inevitable, both as an engineer and as a manager. You're gonna make mistakes. Your team is gonna make mistakes. Facebook talks about moving fast and breaking things. It's a cute saying but it's also a bit of a truism because we work in this field where the ecosystem around us moves fast. We're using new frameworks, new technologies, new languages, new best practices on an almost daily basis. And when we move that fast and try to push the state of the art at the pace that we do, we're gonna make mistakes. Now the thing about this building and the 25,000 ton skeleton that Bill LeMesure created for it is it served as a model for skyscrapers that followed it. Without the innovative work that Bill LeMesure did here, we wouldn't have buildings like Taipei 101 or the Burj Khalifa. You need these lightweight steel skeletons to be able to build taller. You need to be able to support the load of a building by means other than compression strength and that was what Bill LeMesure brought to the table here. He pushed the state of the art of engineering and he made a mistake doing it. But it wasn't an uncorrectable mistake. And by figuring out how to correct his mistake, he allowed the state of his art to move forward and he allowed his building to succeed. Same thing applies to us. If you're going fast and you're innovating, you're going to make mistakes both as an individual developer and as a company. So one of the best investments you can make is learning what to do when you make one of those mistakes, learning how to conduct yourself. Because that, building a team that is supportive of mistakes and knows how to handle them, is a very important part of being able to innovate. Thanks a lot.