A brilliant interactive visualization of primes with mysteriously simplified introductory text.
A prime number is a number greater than one that cannot be divided evenly by any numbers except one and itself.
What we see here is the numbers from 1 to 62,500 laid out in order, where the prime numbers are bright squares and non-primes (“composites”) are dim squares.
As you can see, the grid looks a lot like an office building at night: seemingly random which windows are lit and which are dark. Yet there are columns free of primes — our first sign of order in the constellation of numbers.
The nature of numbers and the occurrence of primes is a central problem in a field of mathematics called “number theory”. Very smart people have been working very hard for a very long time–but the secret of prime numbers remains elusive. There is no efficient equation to generate every prime, or even to always generate a prime.
Info Aesthetics has more links on primes.