## “There are 10 kinds of people in the world: those who understand binary numerals, and those who don’t”*…

From a collection of vintage photos of computing equipment by “design and tech obsessive” James Ball…

More at Docubyte…

[TotH to Kottke]

* vernacular joke, as invoked by Ian Stewart in *Professor Stewart’s Cabinet of Mathematical Curiosities*

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**As we rewind,** we might spare a thought for Christian Goldbach; he died on this date in 1764. A mathematician, lawyer, and historian who studied infinite sums, the theory of curves and the theory of equations, he is best remembered for his correspondence with Leibniz, Euler, and Bernoulli, especially his 1742 letter to Euler containing what is now known as “Goldbach’s conjecture.”

In that letter he outlined his famous proposition:

Every even natural number greater than 2 is equal to the sum of two prime numbers.

It has been checked by computer for vast numbers– up to at least 4 x 1014– but remains unproved.

(Goldbach made another conjecture that every odd number is the sum of three primes; it has been checked by computer for vast numbers, but also remains unproved.)

Goldbach’s letter to Euler* (source, and larger view)*

*(Roughly) Daily* is headed into a Thanksgiving hiatus; regular service will resume when the tryptophan haze clears… probably around Monday, November 26. Thanks for reading– and have Happy Holidays!