• A tetromino is a geometric shape composed of four squares, connected orthogonally. This, like dominoes and pentominoes, is a particular type of polyomino. The corresponding polycube, called a tetracube, is a geometric shape composed of four cubes connected orthogonally. A popular use of tetrominoes is in the video game Tetris, which refers to them under the name tetrimino. The tetrominoes used in the game are specifically the one-sided tetrominoes. [Wiki]
  • On Jeopardy, a player cannot ring in until Alex has finished reading the question. The way Jeopardy accomplishes this is by stationing a production assistant off stage and arming him with a device with a button on it. When the assistant feels that Alex is done reading the question, he presses his button and two things happen simultaneously. Small pin lights in the middle of panels surrounding the playing board go on, and an electrical impulse is sent to the buzzers, activating them. If you press your button before the assistant presses his, you really do get locked out for 1/5 of a second. If you keep ringing in before the lock out is over, you keep getting locked out, I think, but the total lock out time seems like it cannot exceed about a second. (Note that I am guessing about that from experience, I have not talked to any Jeopardy techies about this.) [link]
  • You see, Jeopardy is not a knowledge game. It's a buzzer strategy game. You need to push the buzzer before you are certain of your correct answer. I wasn't ready for it. Before my brain acknowledged I knew the answer, the other two already buzzed in. [link]
  • Magnetic shifts happen faster the closer to the poles you go, so airports at high latitudes must make more frequent adjustments than airports closer to the equator. For Fairbanks International Airport, for example, the interval of change is roughly every 24 years. The overall goal for all navigational aids, according to guidelines in FAA Order 8260, is to keep the magnetic variation figure used for guidance as closely aligned to the current computed value as modeled by the World Magnetic Model, within 1 degree, plus or minus. [NOAA]
  • We teach our students the basics of Airport Engineering including design principles for airside and landside facilities. The most important airside facility is the runway and there are several factors affecting the determination of runway configuration and orientation. Even for single runways, these factors are critical in order to ensure safe and efficient operations. [link]
  • On his first day of a holiday in Switzerland, YouTuber Gursk3 decided to try hang gliding, but the excursion didn't go exactly as planned. He was supposed to be safely tethered to the hang glider and just along for a leisurely ride while a skilled pilot steered the craft down a steep mountain. But shortly after takeoff, the pair realised that his harness hadn't been connected to the glider at all, resulting in Gursk3 having to spend two minutes and 14 seconds desperately clinging to the craft while the pilot attempted to find a safe place to quickly land. [link]
  • Top Democrats believe that anti-monopolism can be a political winner for their party. It's a way to address voters' anxiety over high drug prices, digital privacy and more. "The control of business over certain segments of the economy," says Senator Amy Klobuchur of Minnesota, a potential presidential candidate, "I think it will be a much bigger thing going into 2020." [NY Times]
  • The evidence thus far suggests that forecasters either do not have the information or the incentives to forecast recessions. Lack of information could arise for various reasons. First, data on the economy may only became available with long lags or be of poor quality. Second, economic models may not be good enough to be able to predict outlier events, Third, recessions may occur because of events which are themselves difficult to predict. Lack of incentives could also arise for various reasons. For instance, the reputational loss from being wrong may be higher than the gain from being right. [IMF]