The story behind this piece
In 1963 Stanisław Ulam, doodling in a dull lecture, wrote the integers in a square spiral and marked the primes — and found them crowding onto diagonal lines. This plate winds out from 1 at the centre through some 48,000 integers across the face and wrap. Each prime, found by a sieve of Eratosthenes, glows gold — brighter the more prime diagonal neighbours it has — and touching primes are joined so lines read across the room. Copper marks Euler's polynomial n² + n + 41, prime for every n from 0 to 39; from n = 39 on, its values run along two diagonal rays. The inset shows the first 81 numbers to check the rule. Hardy and Littlewood's Conjecture F predicts which diagonals are rich; it remains unproved.
