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7 Famous Baseball Pitches (and some physics behind them)

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If you haven't noticed, it's October, and that means Major League Baseball playoffs are upon us. If you're watching from home, or listening in on the radio, you'll hear a lot of talk about what kind of pitch was just thrown, will be thrown, should be thrown, might be thrown, or, perhaps, shouldn't have been thrown. Cutters, sliders, sinkers—what are they exactly and what's the difference between them? Here's a little primer on six of the most popular pitches out there and a bit of the physics behind them:

2-seamuse.jpg1. Fastball - This is the basic, most important pitch in baseball. As you see in the picture, the first two fingers rest just on (or inside) the seams and the pitcher releases the pitch with the palm pretty much facing the batter, producing maximum velocity. How fast are we talking? Generally in the 90-95 mph range, though some pitchers have been known to hurl over 100 mph. Technically, what you see in the photo is called a two-seam fastball and produces a sidespin that causes the ball to cut in as it approaches the batter. There are other varieties, like the 4-seam fastball, which is thrown by holding the ball with the seams horizontal, rather than vertical. This produces backspin, which creates high pressure under the ball and low pressure on top resulting in the illusion of the ball rising (actually the ball isn't rising, just falling more slowly than it would normally). There's also a split-finger fastball where the first two fingers split, or straddle the seams, which causes the ball to drop a little as it approaches the plate. Despite the movement, the basic idea of a fastball is to overpower the batter, so he swings late and misses.

sinker.jpg2. Sinker - If you've ever played wiffleball, you know the ball rises, falls, and curves in and away from a batter depending on where you position the air holes in the ball. Likewise, in baseball, a pitcher can create movement and variation in speed depending on how he releases the ball, or how he spins the ball. Off-speed pitches, like the sinker, are pitches that are released with the palm of the hand facing away from the pitcher. This causes the ball to sink as it approaches the batter. The idea here is to either get him to swing over the ball and miss, or, if he connects with the pitch, to produce a ground ball, rather than a line drive.

changeup.jpg3. Changeup - A changeup is like a sinker, in that it's an off-speed pitch, only the palm is turned even further out. All off-speed pitches are similar in that they're thrown with less velocity than the fastball. But the batter doesn't know when one is coming because a good pitcher is able to use the same arm speed as he does for the fastball. So how does he throw it with less velocity? Simple: by pressing the baseball deep into his palm. Less finger contact means less torque and less velocity. So, if a batter is expecting a fastball, slowing down, or "changing up" the speed to, say, 87 mph can trip him up and he'll swing ahead of the ball. Great pitchers can build an entire career on the changeup because they're able to slow it down all the way to around 80 mph. If they can throw a fastball around 95 mph, that's a whopping 15 mph slower and really confuses the batter.

screwball.jpg4. Screwball - This is another off-speed pitch that not only sinks, but moves from the pitcher's left side to the right as it approaches the batter. The palm is again pronated away from the pitcher, even further than the sinker and changeup. As the pitcher releases the ball, he twists the ball like a corkscrew. A left-handed batter will see the ball break away from him and a right-handed batter will experience the opposite, as the ball breaks in on him (the reverse is true if the pitcher is left-handed, of course).

cutter.jpg5. Cutter - Turning the palm in the opposite direction produces a series of pitches known as breaking pitches. The further the palm is rotated toward the pitcher, the more movement (in most cases, but not all). The first stop over from the fastball is the cutter, which is like a fastball, only it breaks in ever so slightly and is generally thrown a few mphs slower than a fastball.

slider.jpg6. Slider - Basically the same thing as a cutter, a slider is thrown with less velocity than the former and the palm is rotated further toward the pitcher. The slower speed means there's more time for the ball to move, or slide, from one side of the plate to the other.

bodyshotcurve.jpg7. Curveball - A good curveball can be devastating, and also fun to watch. These are the pitches that appear to arc up toward the batter's chest (or even head) before dropping into the strike zone like a bomb as they reach the plate. Of course, not every successful curveball pitcher throws the large arc variety and they need not be so dramatic. Even a small arc keeps the hitter off balance. So how is the amazing trajectory accomplished? The pitcher turns his palm in so far that his hand looks like the letter "C." He then flicks his wrist as he releases the ball (the opposite direction from the screwball) creating topspin. The more topspin, the greater the air pressure difference between the top and bottom of the ball, and the greater the break.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Nick Briggs/Comic Relief
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What Happened to Jamie and Aurelia From Love Actually?
May 26, 2017
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Nick Briggs/Comic Relief

Fans of the romantic-comedy Love Actually recently got a bonus reunion in the form of Red Nose Day Actually, a short charity special that gave audiences a peek at where their favorite characters ended up almost 15 years later.

One of the most improbable pairings from the original film was between Jamie (Colin Firth) and Aurelia (Lúcia Moniz), who fell in love despite almost no shared vocabulary. Jamie is English, and Aurelia is Portuguese, and they know just enough of each other’s native tongues for Jamie to propose and Aurelia to accept.

A decade and a half on, they have both improved their knowledge of each other’s languages—if not perfectly, in Jamie’s case. But apparently, their love is much stronger than his grasp on Portuguese grammar, because they’ve got three bilingual kids and another on the way. (And still enjoy having important romantic moments in the car.)

In 2015, Love Actually script editor Emma Freud revealed via Twitter what happened between Karen and Harry (Emma Thompson and Alan Rickman, who passed away last year). Most of the other couples get happy endings in the short—even if Hugh Grant's character hasn't gotten any better at dancing.

[h/t TV Guide]

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