Ulam's Spiral - is a simple method of visualizing the prime numbers that reveals the apparent tendency of certain quadratic polynomials to generate unusually large numbers of primes. It was discovered by the mathematician Stanislaw Ulam in 1963, while he was doodling during the presentation of a "long and very boring paper" at a scientific meeting. more: http://en.wikipedia.org/wiki/Ulam_spiral

Visualization : http://shivam-nagar.github.io/ulam-spiral/