## What colors do you get when you spell words in hex?

The hexidecimal color #C0FFEE (192 Red, 255 Green, 238 Blue, on a scale of 0-255) is a pleasing greenish color, while #BEADED is a kind of mauve. Read the rest

## Numberphile looks at mathematics' undecidable statements

The average person probably assumes that mathematics is a complete system in which all mathematical statements can be proved or disproved. The fine folks at Numberphile are ready to disabuse folks of this notion with a nice overview of Gödel's Incompleteness Theorem. Read the rest

## Kickstarting a CC-licensed picture book that teaches mathematical functions to small kids

Maria writes, "Funville Adventures is a creative, joyful, and gentle new project that introduces young children to advanced math. Children as young as 5 will enjoy the story and math-rich play; older children and adults can also investigate the deeper mathematical concepts such as inverse function, composition, and functional." Read the rest

## Trippy fractal of classical architecture set to classical music

Depths of Antiquity is Julius Horsthuis' hypnotic slow-motion dive into fractals generated from images of churches, castles and other imposing edifices of yesteryear. It's perfectly complemented by Beethoven. Read the rest

## How much would a star destroyer cost?

Generation Tech has done a few fun videos estimating the costs of items in the Star Wars universe. In the latest installment, they calculate the cost of a star destroyer. Spoilers below. Read the rest

## How many lentils does one Spotify play buy you?

theydidthemath is a fun subreddit. In this post a fellow named Nym figured out how many lentils a recording artist can can buy each time someone plays one of their songs. The assumption is that one Spotify play is worth a half cent, and lentils cost \$1.50 a pound. Read the rest

## Mathematical conjecture generates beautiful lifelike form

The deceptively simple Collatz Conjecture is one of mathematics' most difficult puzzles. Alex Bellos shows off a cool rendering by Edmund Harris that looks like a beautiful life form from the sea. Read the rest

## Turns out Star Trek redshirts are not likeliest to die

The Museum of Mathematics recently hosted James Grime's talk "Star Trek: The Math of Khan." He debunked a common stereotype about the show's security detail: redshirts are not the most likely crew to die. Read the rest

## Different ways to prove that .999... = 1

In 2012, Vi Hart made this video giving "9.999... reasons that .999... = 1" She also made a video of bad proofs why .999... does not equal 1.

## The mathematics of how sperm swim

A better understanding how a sperm swims its way toward an egg could help inform new treatments for male infertility. Researchers from the University of York have now come up with a mathematical formula to model how large numbers of moving sperm interact with fluid they're swimming through. From the University:

By analysing the head and tail movements of the sperm, researchers have now shown that the sperm moves the fluid in a coordinated rhythmic way, which can be captured to form a relatively simple mathematical formula. This means complex and expensive computer simulations are no longer needed to understand how the fluid moves as the sperm swim.

The research demonstrated that the sperm has to make multiple contradictory movements, such as moving backwards, in order to propel it forward towards the egg.

The whip-like tail of the sperm has a particular rhythm that pulls the head backwards and sideways to create a jerky fluid flow, countering some of the intense friction that is created due to their diminutive sizes.

“It is true when scientists say how miraculous it is that a sperm ever reaches an egg, but the human body has a very sophisticated system of making sure the right cells come together," (says University of York mathematician Hermes Gadêlha.)

“You would assume that the jerky movements of the sperm would have a very random impact on the fluid flow around it, making it even more difficult for competing sperm cells to navigate through it, but in fact you see well defined patterns forming in the fluid around the sperm.

## Is mathematics invented or discovered?

One of the most interesting series ever is Closer To Truth, which "presents the world’s greatest thinkers exploring humanity’s deepest questions." For instance: is mathematics invented or discovered? Read the rest

## How long would it take a pay-it-forward chain to reach 7.4 billion people?

High school teacher Joe Howard (the guy who made the "How loud would it be if all of the cats in the world meowed at the same time?" video I posted a couple of weeks ago, is back. This time, he shows how to come up with a formula to determine how long would it take a pay-it-forward chain to reach 7.4 billion people

Many people are familiar with the concept of paying forward, but how quickly can it actually spread if we commit to it? This video calculates how many layers of pay it forward would need to happen successfully for the chain to reach everyone on the planet.

## The moving sofa math problem: still unsolved 50 years later

Ever try to move a sofa down a hallway that has a corner? The underlying math behind it inspired a math problem that's been a puzzler since 1966. Gerver's Sofa above shows the parameters: a U-shaped sofa moving around a 90-degree corner in an even-width hallway. Gerver's got the record so far, and it is likely the optimal sofa. Read the rest

## This Mondrian math puzzle yields puzzling scores

Mathematician Gordon Hamilton presents a curious puzzle inspired by the art of Piet Mondrian: within a square canvas filled with rectangles that all have different dimensions, what's the lowest possible score when subtracting the smallest rectangle's area from the largest? Read the rest

## Vi Hart's statistical perspective on the American electoral divide

Fast-talking national-treasure math vlogger Vi Hart (previously) takes a statistical look at the polling data from the 2016 presidential election and concludes that the most significant divide in the country is "old vs young," which drives things like rural/urban (because young people leave failing rural areas for cities) and even racial divides. Read the rest

## Donald Duck is a quite effective and surreal math teacher

"Donald in Mathmagic Land" was released in 1959. As Walt Disney said, "The cartoon is a good medium to stimulate interest."

## The best place to sit in a "suicide circle" if you really don't want to die

Math problems are more interesting when they are posed as horror stories.

The Josephus Problem gets its name from Titus Flavius Josephus, a first-century Jewish scholar.

The story goes that he was with 40 other soldiers when they were surrounded by conquering Romans - imagine that scene in Games of Thrones, where Ramsay Bolton's men trap Jon Snow's army in a tight circle and start moving in.

Rather than give themselves up, the soldiers decided to commit suicide en mass, but by killing each other rather than themselves, to avoid any last-minute changes of heart. Sitting in a circle, the first soldier would kill the man to the left of him, the next living soldier would kill the man to his left, and so on around the circle.

When the circle of slaughter got back to the start, the process would repeat with the smaller group of people. Finally, the last man alive would fall on his sword.

Josephus' problem was that he was much keener on living than dying - but he didn't want to let his fellow soldiers in on that secret. So, where should he position himself in the circle to be the last man standing?