## Pi approximation

The closest approximation of Pi for nearly a thousand years was calculated by Chinese mathematician Zu Chongzhi around 480 CE, using an algorithm developed by Liu Hui.

The closest approximation of Pi for nearly a thousand years was calculated by Chinese mathematician Zu Chongzhi around 480 CE, using an algorithm developed by Liu Hui.

Take a cone, sphere, and cylinder of equal height and radius. The volume of the cone plus the volume of the sphere is equal to the volume of the cylinder.

Within the first thousand digits of pi there are six nines in a row. This should not be a surprise.

The cellular automaton Langton’s Ant follows just two simple commands, and in doing so moves in turn from symmetry to chaos to implacable order.

“One. A Poem. A Raven. Midnights so dreary, tired and weary, silently pondering volumes extolling all by-now obsolete lore.” The beginning of a short story that also encodes the first 3835 digits of pi.

If you want a job as a programmer, you need to know how to fizz buzz.

In 1945 the linguist George Zipf observed two strange word frequency phenomena: the longer a word is, the less common it is; and the most common word is used twice as much as the second most common, three times more than the third.

Imagine an experiment which only works one time in a thousand. If you do that experiment a thousand times, what’s the probability that it works at least once? Counter-intuitively, it’s 63.2%.

There is a courtyard gallery in the Palazzo Spada in Rome that is designed to fool the eye. It looks like it should be 37 metres long, but in fact it’s only 8 metres in total.

Worshippers of many different religious use beads on a string to count prayers: Catholic Christians, Muslims, Buddhists, Sikhs, Hindus, and Baháʼís.

The inventor of the pie chart and the bar chart was also a secret agent who helped collapse the French revolutionary government’s economy through an elaborate counterfeiting operation.

The P vs. NP problem is perhaps the biggest unsolved question in computer science – but an answer would have profound implications for mathematics, cryptography, cancer research, nurse roster scheduling, and sudoku. [2 of 2]

The P vs. NP problem is perhaps the biggest unsolved question in computer science – but an answer would have profound implications for mathematics, cryptography, cancer research, nurse roster scheduling, and sudoku. [1 of 2]

The Darb-e Imam shrine in Iran contains an early and exciting example of non-periodic tiling that was only mathematically appreciated five hundred years later.

Is Christmas Day the twelfth day of Christmas or the first? And why does it cost US$170,298.03?